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.

• libssh2 1.11.1-6 (bug https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1144415) [trixie] - libssh2 (Minor issue; can be fixed via point release) https://github.com/bikini/exploitarium/tree/main/libssh2-publickey-list-calc-poc https://github.com/libssh2/libssh2/pull/2127 Fixed by: https://github.com/libssh2/libssh2/commit/a9758da45a52bc8c630ec9493804d0c6ea30b24a