Description
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.
Severity (CVSS)
| Base score | 8.3 |
|---|---|
| Severity | High |
| Version | CVSS 4.0 |
| Vector | CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N |
| Provided by | CNA |
Weaknesses
- CWE-908 — Use of Uninitialized Resource
Affected products
| Vendor | Product | Versions |
|---|---|---|
| libssh2 | libssh2 | 0 to <=1.11.1 |
References
- https://github.com/bikini/exploitarium/tree/main/libssh2-publickey-list-calc-poc (exploit third-party-advisory)
- https://github.com/libssh2/libssh2/blob/master/src/publickey.c (product)
- https://www.vulncheck.com/advisories/libssh2-free-of-uninitialized-pointer-in-publickey-list-cleanup (third-party-advisory)
Generated from the official CVE List on 28 Jun 2026 07:01 UTC.