Vulnerability-Lookup

brew-libssh2-cve-2026-58050

Vulnerability from osv_homebrew

Published

2026-07-18 04:02

Modified

2026-07-18 04:02

Summary

libssh2 - Integer Overflow in publickey Subsystem Attribute Allocation

Details

libssh2 through 1.11.1 reads an attacker-controlled 32-bit attribute count from a publickey-subsystem response and uses it in the allocation num_attrs * sizeof(libssh2_publickey_attribute) without bounds checking, so on 32-bit platforms the multiplication overflows to an undersized buffer. A malicious SSH server can then drive the attribute-parsing loop to write past the allocation, causing a heap buffer overflow in a connecting libssh2 client.

Severity

8.3 (High)


                    
                      CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N

References

URL

Type

	https://github.com/libssh2/libssh2/blob/master/sr…	WEB
	https://github.com/CVEProject/cvelistV5/tree/main…	ADVISORY
	https://nvd.nist.gov/vuln/detail/CVE-2026-58050	ADVISORY
	https://www.vulncheck.com/advisories/libssh2-inte…	ADVISORY
	https://github.com/bikini/exploitarium/tree/main/…	EVIDENCE

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "fix": "patch",
        "patches": [
          {
            "file": "Patches/libssh2/CVE-2026-58050.patch",
            "type": "backport"
          }
        ]
      },
      "package": {
        "ecosystem": "Homebrew",
        "name": "libssh2",
        "purl": "pkg:brew/libssh2"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.11.1_3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "source": "generated"
  },
  "details": "libssh2 through 1.11.1 reads an attacker-controlled 32-bit attribute count from a publickey-subsystem response and uses it in the allocation num_attrs * sizeof(libssh2_publickey_attribute) without bounds checking, so on 32-bit platforms the multiplication overflows to an undersized buffer. A malicious SSH server can then drive the attribute-parsing loop to write past the allocation, causing a heap buffer overflow in a connecting libssh2 client.",
  "id": "BREW-libssh2-CVE-2026-58050",
  "modified": "2026-07-18T04:02:33Z",
  "published": "2026-07-18T04:02:33Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/libssh2/libssh2/blob/master/src/publickey.c"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/58xxx/CVE-2026-58050.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-58050"
    },
    {
      "type": "ADVISORY",
      "url": "https://www.vulncheck.com/advisories/libssh2-integer-overflow-in-publickey-subsystem-attribute-allocation"
    },
    {
      "type": "EVIDENCE",
      "url": "https://github.com/bikini/exploitarium/tree/main/libssh2-publickey-list-calc-poc"
    }
  ],
  "schema_version": "1.7.3",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "libssh2 - Integer Overflow in publickey Subsystem Attribute Allocation",
  "upstream": [
    "CVE-2026-58050"
  ]
}

CVE-2026-58050 (GCVE-0-2026-58050)

Vulnerability from cvelistv5 – Published: 2026-06-28 01:32 – Updated: 2026-06-29 12:27

Title

libssh2 - Integer Overflow in publickey Subsystem Attribute Allocation

Summary

Severity

7 (High)


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

8.3 (High)


                        
                          CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-06-29 12:26 UTC

CWE

CWE-190 - Integer Overflow or Wraparound

Assigner

VulnCheck mitre root

References

3 references

URL	Tags
https://github.com/bikini/exploitarium/tree/main/…	exploitthird-party-advisory
https://github.com/libssh2/libssh2/blob/master/sr…	product
https://www.vulncheck.com/advisories/libssh2-inte…	third-party-advisory

Impacted products

1 product

Vendor	Product	Version
libssh2	libssh2	Affected: 0 , ≤ 1.11.1 (semver) cpe:2.3:a:libssh2:libssh2::::::::

Date Public

2026-06-25 00:00

Credits

ashdfrkl

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-58050",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-06-29T12:26:56.794862Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-06-29T12:27:17.078Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "affected",
          "product": "libssh2",
          "vendor": "libssh2",
          "versions": [
            {
              "lessThanOrEqual": "1.11.1",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:a:libssh2:libssh2:*:*:*:*:*:*:*:*",
                  "versionEndIncluding": "1.11.1",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "ashdfrkl"
        }
      ],
      "datePublic": "2026-06-25T00:00:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "value": "libssh2 through 1.11.1 reads an attacker-controlled 32-bit attribute count from a publickey-subsystem response and uses it in the allocation num_attrs * sizeof(libssh2_publickey_attribute) without bounds checking, so on 32-bit platforms the multiplication overflows to an undersized buffer. A malicious SSH server can then drive the attribute-parsing loop to write past the allocation, causing a heap buffer overflow in a connecting libssh2 client."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "HIGH",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 7,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "LOW",
            "integrityImpact": "LOW",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:H",
            "version": "3.1"
          },
          "format": "CVSS"
        },
        {
          "cvssV4_0": {
            "attackComplexity": "HIGH",
            "attackRequirements": "NONE",
            "attackVector": "NETWORK",
            "baseScore": 8.3,
            "baseSeverity": "HIGH",
            "privilegesRequired": "NONE",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "NONE",
            "vectorString": "CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N",
            "version": "4.0",
            "vulnAvailabilityImpact": "HIGH",
            "vulnConfidentialityImpact": "LOW",
            "vulnIntegrityImpact": "LOW"
          },
          "format": "CVSS"
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-190",
              "description": "Integer Overflow or Wraparound",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-06-28T01:32:53.582Z",
        "orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
        "shortName": "VulnCheck"
      },
      "references": [
        {
          "name": "Proof of Concept",
          "tags": [
            "exploit",
            "third-party-advisory"
          ],
          "url": "https://github.com/bikini/exploitarium/tree/main/libssh2-publickey-list-calc-poc"
        },
        {
          "name": "src/publickey.c",
          "tags": [
            "product"
          ],
          "url": "https://github.com/libssh2/libssh2/blob/master/src/publickey.c"
        },
        {
          "name": "VulnCheck Advisory: libssh2 - Integer Overflow in publickey Subsystem Attribute Allocation",
          "tags": [
            "third-party-advisory"
          ],
          "url": "https://www.vulncheck.com/advisories/libssh2-integer-overflow-in-publickey-subsystem-attribute-allocation"
        }
      ],
      "title": "libssh2 - Integer Overflow in publickey Subsystem Attribute Allocation",
      "x_generator": {
        "engine": "vulncheck-endgame"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
    "assignerShortName": "VulnCheck",
    "cveId": "CVE-2026-58050",
    "datePublished": "2026-06-28T01:32:53.582Z",
    "dateReserved": "2026-06-28T00:55:25.426Z",
    "dateUpdated": "2026-06-29T12:27:17.078Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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.