Vulnerability-Lookup

CVE-2026-63388 (GCVE-0-2026-63388)

Vulnerability from cvelistv5 – Published: 2026-08-20 17:44 – Updated: 2026-08-21 21:46

Title

Libevent: Heap out-of-bounds write in bufferevent_socket_set_conn_address_ reachable via AF_UNIX accept

Summary

Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent has a heap out-of-bounds write in bufferevent_sock.c when bufferevent_socket_set_conn_address_ copies a kernel-supplied AF_UNIX peer address into bufferevent_private.conn_address. Release builds compiled with NDEBUG disable the EVUTIL_ASSERT length guard, and the evhttp accept path can pass a 110-byte sockaddr from accept() into the 28-byte field. An unauthenticated local peer able to connect to an AF_UNIX listener can overwrite the adjacent dns_request pointer and heap data, causing memory corruption with confidentiality, integrity, and availability impact. This issue is fixed in versions 2.1.13 and 2.2.2-alpha.

Severity

8.4 (High)


                        
                          CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-21 21:00 UTC

CWE

CWE-617 - Reachable Assertion
CWE-787 - Out-of-bounds Write

Assigner

GitHub_M mitre root

References

5 references

URL	Tags
https://github.com/libevent/libevent/security/adv…	x_refsource_CONFIRM
https://github.com/libevent/libevent/commit/52057…	x_refsource_MISC
https://github.com/libevent/libevent/commit/ef38f…	x_refsource_MISC
https://github.com/libevent/libevent/releases/tag…	x_refsource_MISC
https://github.com/libevent/libevent/releases/tag…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version	CPE status
libevent	libevent	Affected: < 2.1.13 Affected: >= 2.2.0-alpha, < 2.2.2-alpha	guessed

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-63388",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-08-21T21:00:24.903079Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-08-21T21:46:40.675Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "libevent",
          "vendor": "libevent",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 2.1.13"
            },
            {
              "status": "affected",
              "version": "\u003e= 2.2.0-alpha, \u003c 2.2.2-alpha"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent has a heap out-of-bounds write in bufferevent_sock.c when bufferevent_socket_set_conn_address_ copies a kernel-supplied AF_UNIX peer address into bufferevent_private.conn_address. Release builds compiled with NDEBUG disable the EVUTIL_ASSERT length guard, and the evhttp accept path can pass a 110-byte sockaddr from accept() into the 28-byte field. An unauthenticated local peer able to connect to an AF_UNIX listener can overwrite the adjacent dns_request pointer and heap data, causing memory corruption with confidentiality, integrity, and availability impact. This issue is fixed in versions 2.1.13 and 2.2.2-alpha."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "LOCAL",
            "availabilityImpact": "HIGH",
            "baseScore": 8.4,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "HIGH",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-617",
              "description": "CWE-617: Reachable Assertion",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-787",
              "description": "CWE-787: Out-of-bounds Write",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-20T17:44:18.435Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/libevent/libevent/security/advisories/GHSA-cvq5-vrvr-j338",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/libevent/libevent/security/advisories/GHSA-cvq5-vrvr-j338"
        },
        {
          "name": "https://github.com/libevent/libevent/commit/52057cb33d0c20c0a0453fbabe6c0c96854931b9",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/libevent/libevent/commit/52057cb33d0c20c0a0453fbabe6c0c96854931b9"
        },
        {
          "name": "https://github.com/libevent/libevent/commit/ef38f926e9cd1f082416c6fff13587bc1f431d72",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/libevent/libevent/commit/ef38f926e9cd1f082416c6fff13587bc1f431d72"
        },
        {
          "name": "https://github.com/libevent/libevent/releases/tag/release-2.1.13-stable",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/libevent/libevent/releases/tag/release-2.1.13-stable"
        },
        {
          "name": "https://github.com/libevent/libevent/releases/tag/release-2.2.2-alpha",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/libevent/libevent/releases/tag/release-2.2.2-alpha"
        }
      ],
      "source": {
        "advisory": "GHSA-cvq5-vrvr-j338",
        "discovery": "UNKNOWN"
      },
      "title": "Libevent: Heap out-of-bounds write in bufferevent_socket_set_conn_address_ reachable via AF_UNIX accept"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-63388",
    "datePublished": "2026-08-20T17:44:18.435Z",
    "dateReserved": "2026-07-16T17:39:30.171Z",
    "dateUpdated": "2026-08-21T21:46:40.675Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-63388",
      "date": "2026-09-15",
      "epss": "0.00142",
      "percentile": "0.03826"
    },
    "microsoft_vex": {
      "current_release_date": "2026-08-25T01:05:12.000Z",
      "cve": "CVE-2026-63388",
      "id": "msrc_CVE-2026-63388",
      "initial_release_date": "2026-08-22T01:03:33.000Z",
      "product_status:known_affected": "6",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "Libevent: Heap out-of-bounds write in bufferevent_socket_set_conn_address_ reachable via AF_UNIX accept",
      "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-63388.json",
      "version": "2"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-63388\",\"sourceIdentifier\":\"security-advisories@github.com\",\"published\":\"2026-08-20T18:16:36.893\",\"lastModified\":\"2026-09-09T21:19:49.197\",\"vulnStatus\":\"Awaiting Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent has a heap out-of-bounds write in bufferevent_sock.c when bufferevent_socket_set_conn_address_ copies a kernel-supplied AF_UNIX peer address into bufferevent_private.conn_address. Release builds compiled with NDEBUG disable the EVUTIL_ASSERT length guard, and the evhttp accept path can pass a 110-byte sockaddr from accept() into the 28-byte field. An unauthenticated local peer able to connect to an AF_UNIX listener can overwrite the adjacent dns_request pointer and heap data, causing memory corruption with confidentiality, integrity, and availability impact. This issue is fixed in versions 2.1.13 and 2.2.2-alpha.\"}],\"affected\":[{\"source\":\"security-advisories@github.com\",\"affectedData\":[{\"vendor\":\"libevent\",\"product\":\"libevent\",\"versions\":[{\"version\":\"\u003c 2.1.13\",\"status\":\"affected\"},{\"version\":\"\u003e= 2.2.0-alpha, \u003c 2.2.2-alpha\",\"status\":\"affected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H\",\"baseScore\":8.4,\"baseSeverity\":\"HIGH\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":2.5,\"impactScore\":5.9}],\"ssvcV203\":[{\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"ssvcData\":{\"timestamp\":\"2026-08-21T21:00:24.903079Z\",\"id\":\"CVE-2026-63388\",\"options\":[{\"exploitation\":\"none\"},{\"automatable\":\"no\"},{\"technicalImpact\":\"total\"}],\"role\":\"CISA Coordinator\",\"version\":\"2.0.3\"}}]},\"weaknesses\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Secondary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-617\"},{\"lang\":\"en\",\"value\":\"CWE-787\"}]}],\"references\":[{\"url\":\"https://github.com/libevent/libevent/commit/52057cb33d0c20c0a0453fbabe6c0c96854931b9\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/libevent/libevent/commit/ef38f926e9cd1f082416c6fff13587bc1f431d72\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/libevent/libevent/releases/tag/release-2.1.13-stable\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/libevent/libevent/releases/tag/release-2.2.2-alpha\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/libevent/libevent/security/advisories/GHSA-cvq5-vrvr-j338\",\"source\":\"security-advisories@github.com\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "Important",
      "current_release_date": "2026-09-11T16:55:13+00:00",
      "cve": "CVE-2026-63388",
      "id": "CVE-2026-63388",
      "initial_release_date": "2026-08-20T17:44:18.435000+00:00",
      "product_status:fixed": "4",
      "product_status:known_affected": "21",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "libevent: Libevent: Arbitrary code execution via heap out-of-bounds write in AF_UNIX handling",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-63388.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "important",
      "current_release_date": "2026-09-15T01:59:31Z",
      "cve": "CVE-2026-63388",
      "id": "CVE-2026-63388",
      "initial_release_date": "2026-08-22T00:56:03Z",
      "product_status:known_affected": "142",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-63388",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-63388.json",
      "version": "4"
    },
    "vulnrichment": {
      "containers": "{\"adp\": [{\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-63388\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"total\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-08-21T21:00:24.903079Z\"}}}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2026-08-21T21:00:26.544Z\"}}], \"cna\": {\"title\": \"Libevent: Heap out-of-bounds write in bufferevent_socket_set_conn_address_ reachable via AF_UNIX accept\", \"source\": {\"advisory\": \"GHSA-cvq5-vrvr-j338\", \"discovery\": \"UNKNOWN\"}, \"metrics\": [{\"cvssV3_1\": {\"scope\": \"UNCHANGED\", \"version\": \"3.1\", \"baseScore\": 8.4, \"attackVector\": \"LOCAL\", \"baseSeverity\": \"HIGH\", \"vectorString\": \"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H\", \"integrityImpact\": \"HIGH\", \"userInteraction\": \"NONE\", \"attackComplexity\": \"LOW\", \"availabilityImpact\": \"HIGH\", \"privilegesRequired\": \"NONE\", \"confidentialityImpact\": \"HIGH\"}}], \"affected\": [{\"vendor\": \"libevent\", \"product\": \"libevent\", \"versions\": [{\"status\": \"affected\", \"version\": \"\u003c 2.1.13\"}, {\"status\": \"affected\", \"version\": \"\u003e= 2.2.0-alpha, \u003c 2.2.2-alpha\"}]}], \"references\": [{\"url\": \"https://github.com/libevent/libevent/security/advisories/GHSA-cvq5-vrvr-j338\", \"name\": \"https://github.com/libevent/libevent/security/advisories/GHSA-cvq5-vrvr-j338\", \"tags\": [\"x_refsource_CONFIRM\"]}, {\"url\": \"https://github.com/libevent/libevent/commit/52057cb33d0c20c0a0453fbabe6c0c96854931b9\", \"name\": \"https://github.com/libevent/libevent/commit/52057cb33d0c20c0a0453fbabe6c0c96854931b9\", \"tags\": [\"x_refsource_MISC\"]}, {\"url\": \"https://github.com/libevent/libevent/commit/ef38f926e9cd1f082416c6fff13587bc1f431d72\", \"name\": \"https://github.com/libevent/libevent/commit/ef38f926e9cd1f082416c6fff13587bc1f431d72\", \"tags\": [\"x_refsource_MISC\"]}, {\"url\": \"https://github.com/libevent/libevent/releases/tag/release-2.1.13-stable\", \"name\": \"https://github.com/libevent/libevent/releases/tag/release-2.1.13-stable\", \"tags\": [\"x_refsource_MISC\"]}, {\"url\": \"https://github.com/libevent/libevent/releases/tag/release-2.2.2-alpha\", \"name\": \"https://github.com/libevent/libevent/releases/tag/release-2.2.2-alpha\", \"tags\": [\"x_refsource_MISC\"]}], \"descriptions\": [{\"lang\": \"en\", \"value\": \"Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent has a heap out-of-bounds write in bufferevent_sock.c when bufferevent_socket_set_conn_address_ copies a kernel-supplied AF_UNIX peer address into bufferevent_private.conn_address. Release builds compiled with NDEBUG disable the EVUTIL_ASSERT length guard, and the evhttp accept path can pass a 110-byte sockaddr from accept() into the 28-byte field. An unauthenticated local peer able to connect to an AF_UNIX listener can overwrite the adjacent dns_request pointer and heap data, causing memory corruption with confidentiality, integrity, and availability impact. This issue is fixed in versions 2.1.13 and 2.2.2-alpha.\"}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-617\", \"description\": \"CWE-617: Reachable Assertion\"}]}, {\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-787\", \"description\": \"CWE-787: Out-of-bounds Write\"}]}], \"providerMetadata\": {\"orgId\": \"a0819718-46f1-4df5-94e2-005712e83aaa\", \"shortName\": \"GitHub_M\", \"dateUpdated\": \"2026-08-20T17:44:18.435Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2026-63388\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-08-21T21:46:40.675Z\", \"dateReserved\": \"2026-07-16T17:39:30.171Z\", \"assignerOrgId\": \"a0819718-46f1-4df5-94e2-005712e83aaa\", \"datePublished\": \"2026-08-20T17:44:18.435Z\", \"assignerShortName\": \"GitHub_M\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}

FKIE_CVE-2026-63388

Vulnerability from fkie_nvd - Published: 2026-08-20 18:16 - Updated: 2026-09-09 21:19

Severity

8.4 (High) - CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Summary

References

	URL	Tags
	security-advisories@github.com	https://github.com/libevent/libevent/commit/52057cb33d0c20c0a0453fbabe6c0c96854931b9
	security-advisories@github.com	https://github.com/libevent/libevent/commit/ef38f926e9cd1f082416c6fff13587bc1f431d72
	security-advisories@github.com	https://github.com/libevent/libevent/releases/tag/release-2.1.13-stable
	security-advisories@github.com	https://github.com/libevent/libevent/releases/tag/release-2.2.2-alpha
	security-advisories@github.com	https://github.com/libevent/libevent/security/advisories/GHSA-cvq5-vrvr-j338

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "libevent",
          "vendor": "libevent",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 2.1.13"
            },
            {
              "status": "affected",
              "version": "\u003e= 2.2.0-alpha, \u003c 2.2.2-alpha"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent has a heap out-of-bounds write in bufferevent_sock.c when bufferevent_socket_set_conn_address_ copies a kernel-supplied AF_UNIX peer address into bufferevent_private.conn_address. Release builds compiled with NDEBUG disable the EVUTIL_ASSERT length guard, and the evhttp accept path can pass a 110-byte sockaddr from accept() into the 28-byte field. An unauthenticated local peer able to connect to an AF_UNIX listener can overwrite the adjacent dns_request pointer and heap data, causing memory corruption with confidentiality, integrity, and availability impact. This issue is fixed in versions 2.1.13 and 2.2.2-alpha."
    }
  ],
  "id": "CVE-2026-63388",
  "lastModified": "2026-09-09T21:19:49.197",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 8.4,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 2.5,
        "impactScore": 5.9,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-63388",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-08-21T21:00:24.903079Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-08-20T18:16:36.893",
  "references": [
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/libevent/libevent/commit/52057cb33d0c20c0a0453fbabe6c0c96854931b9"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/libevent/libevent/commit/ef38f926e9cd1f082416c6fff13587bc1f431d72"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/libevent/libevent/releases/tag/release-2.1.13-stable"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/libevent/libevent/releases/tag/release-2.2.2-alpha"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/libevent/libevent/security/advisories/GHSA-cvq5-vrvr-j338"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Awaiting Analysis",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-617"
        },
        {
          "lang": "en",
          "value": "CWE-787"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Secondary"
    }
  ]
}

MSRC_CVE-2026-63388

Vulnerability from csaf_microsoft - Published: 2026-08-22 01:03 - Updated: 2026-08-25 01:05

Summary

Libevent: Heap out-of-bounds write in bufferevent_socket_set_conn_address_ reachable via AF_UNIX accept

Scope

1 vulnerability in this advisory, including CVE-2026-63388.

CVE-2026-63388

8.4 (High)


                
                  CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Known affected: 6 products

Open the full advisory

RHSA-2026:60853

Vulnerability from csaf_redhat - Published: 2026-08-29 13:59 - Updated: 2026-09-11 16:55

Summary

Red Hat Security Advisory: Red Hat Hardened Images RPMs Security Update

Severity

Important

Scope

5 vulnerabilities in this advisory, including CVE-2026-63388.

CVE-2026-63388

A flaw was found in Libevent. A heap out-of-bounds write vulnerability in the `bufferevent_socket_set_conn_address_` function allows an unauthenticated local peer to achieve arbitrary code execution. By connecting to an AF_UNIX listener, an attacker can overwrite critical heap data, leading to memory corruption and potentially full control over the affected system. This can severely impact the confidentiality, integrity, and availability of data and services.

8.4 (High)


                
                  CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Fixed: 4 products

https://access.redhat.com/errata/RHSA-2026:60853

Open the full advisory

ubuntu-cve-2026-63388

Vulnerability from osv_ubuntu

Published

2026-08-20 18:16

Modified

2026-09-02 16:20

Summary

Details

Severity

8.4 (High)


                    
                      CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

N/A (UNKNOWN)


                    
                      medium

References

URL

Type

	https://ubuntu.com/security/CVE-2026-63388	REPORT
	https://www.cve.org/CVERecord?id=CVE-2026-63388	REPORT

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libevent-2.0-5",
            "binary_version": "2.0.21-stable-1ubuntu1.14.04.2+esm1"
          },
          {
            "binary_name": "libevent-core-2.0-5",
            "binary_version": "2.0.21-stable-1ubuntu1.14.04.2+esm1"
          },
          {
            "binary_name": "libevent-extra-2.0-5",
            "binary_version": "2.0.21-stable-1ubuntu1.14.04.2+esm1"
          },
          {
            "binary_name": "libevent-openssl-2.0-5",
            "binary_version": "2.0.21-stable-1ubuntu1.14.04.2+esm1"
          },
          {
            "binary_name": "libevent-pthreads-2.0-5",
            "binary_version": "2.0.21-stable-1ubuntu1.14.04.2+esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:14.04:LTS",
        "name": "libevent",
        "purl": "pkg:deb/ubuntu/libevent@2.0.21-stable-1ubuntu1.14.04.2+esm1?arch=source\u0026distro=esm-infra-legacy/trusty"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.0.21-stable-1",
        "2.0.21-stable-1ubuntu1",
        "2.0.21-stable-1ubuntu1.14.04.1",
        "2.0.21-stable-1ubuntu1.14.04.2",
        "2.0.21-stable-1ubuntu1.14.04.2+esm1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libevent-2.0-5",
            "binary_version": "2.0.21-stable-2ubuntu0.16.04.1+esm1"
          },
          {
            "binary_name": "libevent-core-2.0-5",
            "binary_version": "2.0.21-stable-2ubuntu0.16.04.1+esm1"
          },
          {
            "binary_name": "libevent-extra-2.0-5",
            "binary_version": "2.0.21-stable-2ubuntu0.16.04.1+esm1"
          },
          {
            "binary_name": "libevent-openssl-2.0-5",
            "binary_version": "2.0.21-stable-2ubuntu0.16.04.1+esm1"
          },
          {
            "binary_name": "libevent-pthreads-2.0-5",
            "binary_version": "2.0.21-stable-2ubuntu0.16.04.1+esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:16.04:LTS",
        "name": "libevent",
        "purl": "pkg:deb/ubuntu/libevent@2.0.21-stable-2ubuntu0.16.04.1+esm1?arch=source\u0026distro=esm-infra-legacy/xenial"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.0.21-stable-2",
        "2.0.21-stable-2ubuntu0.16.04.1",
        "2.0.21-stable-2ubuntu0.16.04.1+esm1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libevent-2.1-6",
            "binary_version": "2.1.8-stable-4ubuntu0.1~esm1"
          },
          {
            "binary_name": "libevent-core-2.1-6",
            "binary_version": "2.1.8-stable-4ubuntu0.1~esm1"
          },
          {
            "binary_name": "libevent-extra-2.1-6",
            "binary_version": "2.1.8-stable-4ubuntu0.1~esm1"
          },
          {
            "binary_name": "libevent-openssl-2.1-6",
            "binary_version": "2.1.8-stable-4ubuntu0.1~esm1"
          },
          {
            "binary_name": "libevent-pthreads-2.1-6",
            "binary_version": "2.1.8-stable-4ubuntu0.1~esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:18.04:LTS",
        "name": "libevent",
        "purl": "pkg:deb/ubuntu/libevent@2.1.8-stable-4ubuntu0.1~esm1?arch=source\u0026distro=esm-infra/bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.1.8-stable-4",
        "2.1.8-stable-4build1",
        "2.1.8-stable-4ubuntu0.1~esm1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libevent-2.1-7",
            "binary_version": "2.1.11-stable-1ubuntu0.1~esm1"
          },
          {
            "binary_name": "libevent-core-2.1-7",
            "binary_version": "2.1.11-stable-1ubuntu0.1~esm1"
          },
          {
            "binary_name": "libevent-extra-2.1-7",
            "binary_version": "2.1.11-stable-1ubuntu0.1~esm1"
          },
          {
            "binary_name": "libevent-openssl-2.1-7",
            "binary_version": "2.1.11-stable-1ubuntu0.1~esm1"
          },
          {
            "binary_name": "libevent-pthreads-2.1-7",
            "binary_version": "2.1.11-stable-1ubuntu0.1~esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:20.04:LTS",
        "name": "libevent",
        "purl": "pkg:deb/ubuntu/libevent@2.1.11-stable-1ubuntu0.1~esm1?arch=source\u0026distro=esm-infra/focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.1.8-stable-4build1",
        "2.1.11-stable-1~exp0",
        "2.1.11-stable-1",
        "2.1.11-stable-1ubuntu0.1~esm1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libevent-2.1-7",
            "binary_version": "2.1.12-stable-1ubuntu0.1"
          },
          {
            "binary_name": "libevent-core-2.1-7",
            "binary_version": "2.1.12-stable-1ubuntu0.1"
          },
          {
            "binary_name": "libevent-extra-2.1-7",
            "binary_version": "2.1.12-stable-1ubuntu0.1"
          },
          {
            "binary_name": "libevent-openssl-2.1-7",
            "binary_version": "2.1.12-stable-1ubuntu0.1"
          },
          {
            "binary_name": "libevent-pthreads-2.1-7",
            "binary_version": "2.1.12-stable-1ubuntu0.1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "libevent",
        "purl": "pkg:deb/ubuntu/libevent@2.1.12-stable-1ubuntu0.1?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.1.12-stable-1",
        "2.1.12-stable-1build1",
        "2.1.12-stable-1build2",
        "2.1.12-stable-1build3",
        "2.1.12-stable-1ubuntu0.1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libevent-2.1-7t64",
            "binary_version": "2.1.12-stable-9ubuntu2.1"
          },
          {
            "binary_name": "libevent-core-2.1-7t64",
            "binary_version": "2.1.12-stable-9ubuntu2.1"
          },
          {
            "binary_name": "libevent-extra-2.1-7t64",
            "binary_version": "2.1.12-stable-9ubuntu2.1"
          },
          {
            "binary_name": "libevent-openssl-2.1-7t64",
            "binary_version": "2.1.12-stable-9ubuntu2.1"
          },
          {
            "binary_name": "libevent-pthreads-2.1-7t64",
            "binary_version": "2.1.12-stable-9ubuntu2.1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:24.04:LTS",
        "name": "libevent",
        "purl": "pkg:deb/ubuntu/libevent@2.1.12-stable-9ubuntu2.1?arch=source\u0026distro=noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.1.12-stable-9",
        "2.1.12-stable-9ubuntu2",
        "2.1.12-stable-9ubuntu2.1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libevent-2.1-7t64",
            "binary_version": "2.1.12-stable-10ubuntu0.1"
          },
          {
            "binary_name": "libevent-core-2.1-7t64",
            "binary_version": "2.1.12-stable-10ubuntu0.1"
          },
          {
            "binary_name": "libevent-extra-2.1-7t64",
            "binary_version": "2.1.12-stable-10ubuntu0.1"
          },
          {
            "binary_name": "libevent-openssl-2.1-7t64",
            "binary_version": "2.1.12-stable-10ubuntu0.1"
          },
          {
            "binary_name": "libevent-pthreads-2.1-7t64",
            "binary_version": "2.1.12-stable-10ubuntu0.1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "libevent",
        "purl": "pkg:deb/ubuntu/libevent@2.1.12-stable-10ubuntu0.1?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.1.12-stable-10build1",
        "2.1.12-stable-10build2",
        "2.1.12-stable-10ubuntu0.1"
      ]
    }
  ],
  "aliases": [],
  "details": "Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent has a heap out-of-bounds write in bufferevent_sock.c when bufferevent_socket_set_conn_address_ copies a kernel-supplied AF_UNIX peer address into bufferevent_private.conn_address. Release builds compiled with NDEBUG disable the EVUTIL_ASSERT length guard, and the evhttp accept path can pass a 110-byte sockaddr from accept() into the 28-byte field. An unauthenticated local peer able to connect to an AF_UNIX listener can overwrite the adjacent dns_request pointer and heap data, causing memory corruption with confidentiality, integrity, and availability impact. This issue is fixed in versions 2.1.13 and 2.2.2-alpha.",
  "id": "UBUNTU-CVE-2026-63388",
  "modified": "2026-09-02T16:20:06Z",
  "published": "2026-08-20T18:16:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-63388"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-63388"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-63388"
  ]
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

Action not permitted

CVE-2026-63388 (GCVE-0-2026-63388)

FKIE_CVE-2026-63388

MSRC_CVE-2026-63388

RHSA-2026:60853

ubuntu-cve-2026-63388

Vulnerability from osv_ubuntu

Tags

Sightings

Nomenclature

Related by attack behaviour