Read the docs
TI-2026-41806 Aliases CVE-2026-58051GHSA-c5f3-hwj2-xp5p

libssh2 - Free of Uninitialized Pointer in publickey List Cleanup

Priority HIGH 69CWE-908Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
High
Attack requirements
None
Impact type
—
Confidentiality · integrity · availability
None · Low · High
Fix status
Partial Red Hat: 1 fixed, 2 without a fix

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and Red Hat.

Summary

libssh2 through 1.11.1 grows its publickey list with SSH2_REALLOC but does not zero-initialize new entries before parsing populates them, so a parse failure reaching the cleanup path leaves libssh2_publickey_list_free operating on an uninitialized entry. A malicious SSH server offering the publickey subsystem can use a malformed response to make cleanup free an uninitialized, attacker-influenceable attrs pointer in a connecting libssh2 client.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00277 20th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by the CNA
Fix Partial Red Hat: 2 advisoriesRed Hat: 1 fixed, 2 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
The libssh2 Projectlibssh2up to 1.11.1—No fix listedCNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:libssh2:libssh2:*:*:*:*:*:*:*:*up to 1.11.1VulnerableThe libssh2 Project
  • cpe:2.3:a:libssh2:libssh2:*:*:*:*:*:*:*:* Versions up to 1.11.1 Vulnerable ·The libssh2 Project

Remediation

Red Hat 2 advisories

  • RHSA-2026:46927 Released 2026-07-27 · Red Hat rating Important
    Red Hat Hardened Images RPMs Security Update
    • Red Hat Hardened Images libssh2-1.11.1-10.2.hum1@aarch64, libssh2-1.11.1-10.2.hum1@src, libssh2-1.11.1-10.2.hum1@x86_64 +4
  • RHSA-2026:46535 Released 2026-07-27 · Red Hat rating Moderate
    Red Hat Hardened Images RPMs Security Update
    • Red Hat Hardened Images libssh2-1.11.1-10.1.hum1@aarch64, libssh2-1.11.1-10.1.hum1@src, libssh2-1.11.1-10.1.hum1@x86_64 +4

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux 6AffectedNo fix planned: Out of support scope
Red Hat Enterprise Linux 7AffectedNo fix planned: Out of support scope
Red Hat Hardened ImagesFixed RHSA-2026:46535, RHSA-2026:46927

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-58051
  2. 2026-10-03 Alias added: GHSA-c5f3-hwj2-xp5p
  3. 2026-11-06 Affected versions changed · Red Hat

References

Exploit 1

Other 1

  • TI-2026-39880 libssh2 - Out-of-Bounds Write via Unchecked packet_length in transport.c CVSS 4.0CRITICAL 9.2
  • TI-2026-06681 libssh2 userauth.c userauth_password integer overflow CVSS 4.0MEDIUM 6.9
  • TI-2023-26623 The SSH transport protocol with certain OpenSSH extensions, found in OpenSSH before 9.6… CVSS 3.1MEDIUM 5.9
  • TI-2019-02869 Out-of-bounds read in libssh2 CVSS 3.1CRITICAL 9.1
  • TI-2019-02865 Integer overflow in libssh2 CVSS 3.1HIGH 8.8
  • TI-2019-02872 Out-of-bounds read in libssh2 CVSS 3.0CRITICAL 9.1
See all 24 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences