Vulnerability-Lookup

BREW-LIBSSH2-CVE-2026-66032 (CVE-2026-66032)

Vulnerability from osv_homebrew – Published: 2026-08-05 16:54 – Updated: 2026-08-05 16:54 – Source website

Summary

libssh2 Double-Free Heap Corruption via sftp_open()

Details

libssh2 through 1.11.1, fixed in commit 5e47761, contains a double-free vulnerability in the sftp_open() function in src/sftp.c that allows a malicious SSH server to corrupt the heap of any authenticated client opening an SFTP session. When a server responds to SSH_FXP_OPEN with SSH_FXP_STATUS containing FX_OK, the response data buffer is freed, and if a subsequent sftp_packet_require() call returns a specific error such as LIBSSH2_ERROR_CHANNEL_PACKET_EXCEEDED, the same pointer is freed a second time, enabling tcache dup conditions on glibc systems that allow overlapping allocations and function pointer overwrites.

Severity

8.7 (High)


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

References

URL

Type

	https://github.com/CVEProject/cvelistV5/tree/main…	ADVISORY
	https://nvd.nist.gov/vuln/detail/CVE-2026-66032	ADVISORY
	https://www.vulncheck.com/advisories/libssh2-doub…	ADVISORY
	https://github.com/libssh2/libssh2/commit/5e47761…	FIX
	https://github.com/libssh2/libssh2/pull/2180	FIX
	https://github.com/libssh2/libssh2	PACKAGE

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "fix": "patch",
        "patches": [
          {
            "file": "Patches/libssh2/CVE-2026-66032.patch",
            "type": "backport"
          }
        ]
      },
      "package": {
        "ecosystem": "Homebrew",
        "name": "libssh2",
        "purl": "pkg:brew/libssh2"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.11.1_4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "source": "generated"
  },
  "details": "libssh2 through 1.11.1, fixed in commit 5e47761, contains a double-free vulnerability in the sftp_open() function in src/sftp.c that allows a malicious SSH server to corrupt the heap of any authenticated client opening an SFTP session. When a server responds to SSH_FXP_OPEN with SSH_FXP_STATUS containing FX_OK, the response data buffer is freed, and if a subsequent sftp_packet_require() call returns a specific error such as LIBSSH2_ERROR_CHANNEL_PACKET_EXCEEDED, the same pointer is freed a second time, enabling tcache dup conditions on glibc systems that allow overlapping allocations and function pointer overwrites.",
  "id": "BREW-libssh2-CVE-2026-66032",
  "modified": "2026-08-05T16:54:10Z",
  "published": "2026-08-05T16:54:10Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/66xxx/CVE-2026-66032.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-66032"
    },
    {
      "type": "ADVISORY",
      "url": "https://www.vulncheck.com/advisories/libssh2-double-free-heap-corruption-via-sftp-open"
    },
    {
      "type": "FIX",
      "url": "https://github.com/libssh2/libssh2/commit/5e4776146552d898b9c0e1b313cd093fa8dc92d0"
    },
    {
      "type": "FIX",
      "url": "https://github.com/libssh2/libssh2/pull/2180"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/libssh2/libssh2"
    }
  ],
  "schema_version": "1.7.3",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "libssh2 Double-Free Heap Corruption via sftp_open()",
  "upstream": [
    "CVE-2026-66032"
  ]
}

CVE-2026-66032 (GCVE-0-2026-66032)

Vulnerability from cvelistv5 – Published: 2026-07-24 16:32 – Updated: 2026-07-28 01:06 X_Open Source

Title

libssh2 Double-Free Heap Corruption via sftp_open()

Summary

Severity

8.7 (High)


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

8.8 (High)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:R/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 2026-07-24 00:00 UTC

CWE

CWE-415 - Double Free

Assigner

VulnCheck mitre root

References

3 references

URL	Tags
https://github.com/libssh2/libssh2/pull/2180	issue-trackingpatch
https://github.com/libssh2/libssh2/commit/5e47761…	patch
https://www.vulncheck.com/advisories/libssh2-doub…	third-party-advisory

Impacted products

1 product

Vendor	Product	Version
libssh2	libssh2	Affected: 0 , ≤ 1.11.1 (semver) Unaffected: 5e4776146552d898b9c0e1b313cd093fa8dc92d0 (git) cpe:2.3:a:libssh2:libssh2::::::::

Date Public

2026-07-02 00:00

Credits

VladimirEliTokarev

Show details on NVD website

JSON

To clipboard

{
  "containers": {
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      {
        "metrics": [
          {
            "other": {
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                "id": "CVE-2026-66032",
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                  },
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                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-07-24T00:00:00+00:00",
                "version": "2.0.3"
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              "type": "ssvc"
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        "providerMetadata": {
          "dateUpdated": "2026-07-25T03:55:50.906Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
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    "cna": {
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              "version": "0",
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            },
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              "version": "5e4776146552d898b9c0e1b313cd093fa8dc92d0",
              "versionType": "git"
            }
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        }
      ],
      "cpeApplicability": [
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          "nodes": [
            {
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            "Recovery": "NOT_DEFINED",
            "Safety": "NOT_DEFINED",
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            "attackRequirements": "NONE",
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    "datePublished": "2026-07-24T16:32:39.596Z",
    "dateReserved": "2026-07-23T20:45:17.816Z",
    "dateUpdated": "2026-07-28T01:06:24.681Z",
    "state": "PUBLISHED"
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  "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.

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.
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BREW-LIBSSH2-CVE-2026-66032 (CVE-2026-66032)

CVE-2026-66032 (GCVE-0-2026-66032)

Tags

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