CVE-2026-58051
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.
CSIRTS triage
- What
- This vulnerability is due to a free of uninitialized pointer in publickey list cleanup.
- Who is affected
- Users of libssh2 are affected by this vulnerability.
- Urgency
- Remediation is urgent due to its medium severity and potential for exploitation.
- Action
- Update to the latest version of libssh2.
AI-assisted analysis generated from the source advisory — verify against the original.
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Exploitation outlook
- Low exploitation risk0.28% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 20% of all EPSS-scored CVEs.
Advisory coverage (2)
External references
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