CVE-2026-11850 (GCVE-0-2026-11850)

Vulnerability from cvelistv5 – Published: 2026-06-11 09:49 – Updated: 2026-06-18 16:05
VLAI
Title
Krb5: krb5: integer underflow in berval2tl_data() leads to heap out-of-bounds read
Summary
An integer underflow vulnerability was found in MIT krb5 in the berval2tl_data() function in plugins/kdb/ldap/libkdb_ldap/ldap_principal2.c. The function performs an unsigned subtraction (bv_len - 2) without a prior bounds check. When bv_len is 0 or 1, the subtraction wraps to a large value which is then truncated to uint16_t, yielding 0xFFFE (65534) or 0xFFFF (65535). The subsequent malloc succeeds and memcpy reads up to 65534 bytes from a 0-1 byte buffer, resulting in a heap out-of-bounds read. The attack vector involves a malicious or compromised LDAP KDB backend returning a krbExtraData attribute with bv_len < 2, triggering the underflow when the KDC or kadmind reads principal data.
Severity
5 (Medium)
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:L/I:N/A:H
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator (v2.0.3)
CWE
  • CWE-191 - Integer Underflow (Wrap or Wraparound)
Assigner
References
URL Tags
https://access.redhat.com/errata/RHSA-2026:25520 vendor-advisoryx_refsource_REDHAT
https://access.redhat.com/security/cve/CVE-2026-11850 vdb-entryx_refsource_REDHAT
https://bugzilla.redhat.com/show_bug.cgi?id=2459970 issue-trackingx_refsource_REDHAT
Impacted products
Date Public
2026-06-10 00:00
Credits
Red Hat would like to thank Sebastián Alba Vives for reporting this issue.
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-11850",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-06-11T12:35:21.860008Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-06-11T12:37:05.721Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "collectionURL": "https://catalog.redhat.com/software/containers/",
          "cpes": [
            "cpe:/a:redhat:hummingbird:1"
          ],
          "defaultStatus": "affected",
          "packageName": "krb5-main",
          "product": "Red Hat Hardened Images",
          "vendor": "Red Hat",
          "versions": [
            {
              "lessThan": "*",
              "status": "unaffected",
              "version": "1.22.2-8.hum1",
              "versionType": "rpm"
            }
          ]
        },
        {
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "cpes": [
            "cpe:/o:redhat:enterprise_linux:10"
          ],
          "defaultStatus": "affected",
          "packageName": "krb5",
          "product": "Red Hat Enterprise Linux 10",
          "vendor": "Red Hat"
        },
        {
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "cpes": [
            "cpe:/o:redhat:enterprise_linux:6"
          ],
          "defaultStatus": "affected",
          "packageName": "krb5",
          "product": "Red Hat Enterprise Linux 6",
          "vendor": "Red Hat"
        },
        {
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "cpes": [
            "cpe:/o:redhat:enterprise_linux:7"
          ],
          "defaultStatus": "affected",
          "packageName": "krb5",
          "product": "Red Hat Enterprise Linux 7",
          "vendor": "Red Hat"
        },
        {
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "cpes": [
            "cpe:/o:redhat:enterprise_linux:8"
          ],
          "defaultStatus": "affected",
          "packageName": "krb5",
          "product": "Red Hat Enterprise Linux 8",
          "vendor": "Red Hat"
        },
        {
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "cpes": [
            "cpe:/o:redhat:enterprise_linux:9"
          ],
          "defaultStatus": "affected",
          "packageName": "krb5",
          "product": "Red Hat Enterprise Linux 9",
          "vendor": "Red Hat"
        },
        {
          "collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
          "cpes": [
            "cpe:/a:redhat:openshift:4"
          ],
          "defaultStatus": "affected",
          "packageName": "rhcos",
          "product": "Red Hat OpenShift Container Platform 4",
          "vendor": "Red Hat"
        }
      ],
      "credits": [
        {
          "lang": "en",
          "value": "Red Hat would like to thank Sebasti\u00e1n Alba Vives for reporting this issue."
        }
      ],
      "datePublic": "2026-06-10T00:00:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "value": "An integer underflow vulnerability was found in MIT krb5 in the berval2tl_data() function in plugins/kdb/ldap/libkdb_ldap/ldap_principal2.c. The function performs an unsigned subtraction (bv_len - 2) without a prior bounds check. When bv_len is 0 or 1, the subtraction wraps to a large value which is then truncated to uint16_t, yielding 0xFFFE (65534) or 0xFFFF (65535). The subsequent malloc succeeds and memcpy reads up to 65534 bytes from a 0-1 byte buffer, resulting in a heap out-of-bounds read.\nThe attack vector involves a malicious or compromised LDAP KDB backend returning a krbExtraData attribute with bv_len \u003c 2, triggering the underflow when the KDC or kadmind reads principal data."
        }
      ],
      "metrics": [
        {
          "other": {
            "content": {
              "namespace": "https://access.redhat.com/security/updates/classification/",
              "value": "Moderate"
            },
            "type": "Red Hat severity rating"
          }
        },
        {
          "cvssV3_1": {
            "attackComplexity": "HIGH",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 5,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "LOW",
            "integrityImpact": "NONE",
            "privilegesRequired": "HIGH",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:L/I:N/A:H",
            "version": "3.1"
          },
          "format": "CVSS"
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-191",
              "description": "Integer Underflow (Wrap or Wraparound)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-06-18T16:05:36.425Z",
        "orgId": "53f830b8-0a3f-465b-8143-3b8a9948e749",
        "shortName": "redhat"
      },
      "references": [
        {
          "name": "RHSA-2026:25520",
          "tags": [
            "vendor-advisory",
            "x_refsource_REDHAT"
          ],
          "url": "https://access.redhat.com/errata/RHSA-2026:25520"
        },
        {
          "tags": [
            "vdb-entry",
            "x_refsource_REDHAT"
          ],
          "url": "https://access.redhat.com/security/cve/CVE-2026-11850"
        },
        {
          "name": "RHBZ#2459970",
          "tags": [
            "issue-tracking",
            "x_refsource_REDHAT"
          ],
          "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2459970"
        }
      ],
      "timeline": [
        {
          "lang": "en",
          "time": "2026-04-21T00:00:00.000Z",
          "value": "Reported to Red Hat."
        },
        {
          "lang": "en",
          "time": "2026-06-10T00:00:00.000Z",
          "value": "Made public."
        }
      ],
      "title": "Krb5: krb5: integer underflow in berval2tl_data() leads to heap out-of-bounds read",
      "workarounds": [
        {
          "lang": "en",
          "value": "Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability."
        }
      ],
      "x_generator": {
        "engine": "cvelib 1.8.0"
      },
      "x_redhatCweChain": "CWE-191: Integer Underflow (Wrap or Wraparound)"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "53f830b8-0a3f-465b-8143-3b8a9948e749",
    "assignerShortName": "redhat",
    "cveId": "CVE-2026-11850",
    "datePublished": "2026-06-11T09:49:07.726Z",
    "dateReserved": "2026-06-10T08:12:34.560Z",
    "dateUpdated": "2026-06-18T16:05:36.425Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-11850",
      "date": "2026-06-26",
      "epss": "0.00261",
      "percentile": "0.17405"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-11850\",\"sourceIdentifier\":\"secalert@redhat.com\",\"published\":\"2026-06-11T10:16:21.217\",\"lastModified\":\"2026-06-12T15:16:24.737\",\"vulnStatus\":\"Awaiting Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"An integer underflow vulnerability was found in MIT krb5 in the berval2tl_data() function in plugins/kdb/ldap/libkdb_ldap/ldap_principal2.c. The function performs an unsigned subtraction (bv_len - 2) without a prior bounds check. When bv_len is 0 or 1, the subtraction wraps to a large value which is then truncated to uint16_t, yielding 0xFFFE (65534) or 0xFFFF (65535). The subsequent malloc succeeds and memcpy reads up to 65534 bytes from a 0-1 byte buffer, resulting in a heap out-of-bounds read.\\nThe attack vector involves a malicious or compromised LDAP KDB backend returning a krbExtraData attribute with bv_len \u003c 2, triggering the underflow when the KDC or kadmind reads principal data.\"}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"secalert@redhat.com\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:L/I:N/A:H\",\"baseScore\":5.0,\"baseSeverity\":\"MEDIUM\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"HIGH\",\"privilegesRequired\":\"HIGH\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"LOW\",\"integrityImpact\":\"NONE\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":0.7,\"impactScore\":4.2}]},\"weaknesses\":[{\"source\":\"secalert@redhat.com\",\"type\":\"Secondary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-191\"}]}],\"references\":[{\"url\":\"https://access.redhat.com/errata/RHSA-2026:25520\",\"source\":\"secalert@redhat.com\"},{\"url\":\"https://access.redhat.com/security/cve/CVE-2026-11850\",\"source\":\"secalert@redhat.com\"},{\"url\":\"https://bugzilla.redhat.com/show_bug.cgi?id=2459970\",\"source\":\"secalert@redhat.com\"}]}}",
    "vulnrichment": {
      "containers": "{\"adp\": [{\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-11850\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-06-11T12:35:21.860008Z\"}}}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2026-06-11T12:36:51.179Z\"}}], \"cna\": {\"title\": \"Krb5: krb5: integer underflow in berval2tl_data() leads to heap out-of-bounds read\", \"credits\": [{\"lang\": \"en\", \"value\": \"Red Hat would like to thank Sebasti\\u00e1n Alba Vives for reporting this issue.\"}], \"metrics\": [{\"other\": {\"type\": \"Red Hat severity rating\", \"content\": {\"value\": \"Moderate\", \"namespace\": \"https://access.redhat.com/security/updates/classification/\"}}}, {\"format\": \"CVSS\", \"cvssV3_1\": {\"scope\": \"UNCHANGED\", \"version\": \"3.1\", \"baseScore\": 5, \"attackVector\": \"NETWORK\", \"baseSeverity\": \"MEDIUM\", \"vectorString\": \"CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:L/I:N/A:H\", \"integrityImpact\": \"NONE\", \"userInteraction\": \"NONE\", \"attackComplexity\": \"HIGH\", \"availabilityImpact\": \"HIGH\", \"privilegesRequired\": \"HIGH\", \"confidentialityImpact\": \"LOW\"}}], \"affected\": [{\"cpes\": [\"cpe:/a:redhat:hummingbird:1\"], \"vendor\": \"Red Hat\", \"product\": \"Red Hat Hardened Images\", \"versions\": [{\"status\": \"unaffected\", \"version\": \"1.22.2-8.hum1\", \"lessThan\": \"*\", \"versionType\": \"rpm\"}], \"packageName\": \"krb5-main\", \"collectionURL\": \"https://catalog.redhat.com/software/containers/\", \"defaultStatus\": \"affected\"}, {\"cpes\": [\"cpe:/o:redhat:enterprise_linux:10\"], \"vendor\": \"Red Hat\", \"product\": \"Red Hat Enterprise Linux 10\", \"packageName\": \"krb5\", \"collectionURL\": \"https://access.redhat.com/downloads/content/package-browser/\", \"defaultStatus\": \"affected\"}, {\"cpes\": [\"cpe:/o:redhat:enterprise_linux:6\"], \"vendor\": \"Red Hat\", \"product\": \"Red Hat Enterprise Linux 6\", \"packageName\": \"krb5\", \"collectionURL\": \"https://access.redhat.com/downloads/content/package-browser/\", \"defaultStatus\": \"affected\"}, {\"cpes\": [\"cpe:/o:redhat:enterprise_linux:7\"], \"vendor\": \"Red Hat\", \"product\": \"Red Hat Enterprise Linux 7\", \"packageName\": \"krb5\", \"collectionURL\": \"https://access.redhat.com/downloads/content/package-browser/\", \"defaultStatus\": \"affected\"}, {\"cpes\": [\"cpe:/o:redhat:enterprise_linux:8\"], \"vendor\": \"Red Hat\", \"product\": \"Red Hat Enterprise Linux 8\", \"packageName\": \"krb5\", \"collectionURL\": \"https://access.redhat.com/downloads/content/package-browser/\", \"defaultStatus\": \"affected\"}, {\"cpes\": [\"cpe:/o:redhat:enterprise_linux:9\"], \"vendor\": \"Red Hat\", \"product\": \"Red Hat Enterprise Linux 9\", \"packageName\": \"krb5\", \"collectionURL\": \"https://access.redhat.com/downloads/content/package-browser/\", \"defaultStatus\": \"affected\"}, {\"cpes\": [\"cpe:/a:redhat:openshift:4\"], \"vendor\": \"Red Hat\", \"product\": \"Red Hat OpenShift Container Platform 4\", \"packageName\": \"rhcos\", \"collectionURL\": \"https://access.redhat.com/downloads/content/package-browser/\", \"defaultStatus\": \"affected\"}], \"timeline\": [{\"lang\": \"en\", \"time\": \"2026-04-21T00:00:00.000Z\", \"value\": \"Reported to Red Hat.\"}, {\"lang\": \"en\", \"time\": \"2026-06-10T00:00:00.000Z\", \"value\": \"Made public.\"}], \"datePublic\": \"2026-06-10T00:00:00.000Z\", \"references\": [{\"url\": \"https://access.redhat.com/errata/RHSA-2026:25520\", \"name\": \"RHSA-2026:25520\", \"tags\": [\"vendor-advisory\", \"x_refsource_REDHAT\"]}, {\"url\": \"https://access.redhat.com/security/cve/CVE-2026-11850\", \"tags\": [\"vdb-entry\", \"x_refsource_REDHAT\"]}, {\"url\": \"https://bugzilla.redhat.com/show_bug.cgi?id=2459970\", \"name\": \"RHBZ#2459970\", \"tags\": [\"issue-tracking\", \"x_refsource_REDHAT\"]}], \"workarounds\": [{\"lang\": \"en\", \"value\": \"Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.\"}], \"x_generator\": {\"engine\": \"cvelib 1.8.0\"}, \"descriptions\": [{\"lang\": \"en\", \"value\": \"An integer underflow vulnerability was found in MIT krb5 in the berval2tl_data() function in plugins/kdb/ldap/libkdb_ldap/ldap_principal2.c. The function performs an unsigned subtraction (bv_len - 2) without a prior bounds check. When bv_len is 0 or 1, the subtraction wraps to a large value which is then truncated to uint16_t, yielding 0xFFFE (65534) or 0xFFFF (65535). The subsequent malloc succeeds and memcpy reads up to 65534 bytes from a 0-1 byte buffer, resulting in a heap out-of-bounds read.\\nThe attack vector involves a malicious or compromised LDAP KDB backend returning a krbExtraData attribute with bv_len \u003c 2, triggering the underflow when the KDC or kadmind reads principal data.\"}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-191\", \"description\": \"Integer Underflow (Wrap or Wraparound)\"}]}], \"providerMetadata\": {\"orgId\": \"53f830b8-0a3f-465b-8143-3b8a9948e749\", \"shortName\": \"redhat\", \"dateUpdated\": \"2026-06-18T16:05:36.425Z\"}, \"x_redhatCweChain\": \"CWE-191: Integer Underflow (Wrap or Wraparound)\"}}",
      "cveMetadata": "{\"cveId\": \"CVE-2026-11850\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-06-18T16:05:36.425Z\", \"dateReserved\": \"2026-06-10T08:12:34.560Z\", \"assignerOrgId\": \"53f830b8-0a3f-465b-8143-3b8a9948e749\", \"datePublished\": \"2026-06-11T09:49:07.726Z\", \"assignerShortName\": \"redhat\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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.