CVE-2026-58051
Published: July 1, 2026Last modified: August 24, 2026
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 score breakdown
| Parameter | Value |
|---|---|
| Base score | 6.5 |
| Attack Vector | NETWORK |
| Attack complexity | HIGH |
| Privileges required | NONE |
| User interaction | NONE |
| Scope | UNCHANGED |
| Confidentiality | NONE |
| Integrity impact | LOW |
| Availability impact | HIGH |
| Vector | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H |
Status
| Product | Release | Package | Status |
|---|---|---|---|
| Alpaquita Linux | 23 LTS | libssh2 | Unknown (1.10.0-r4) |
| 25 LTS | libssh2 | Fixed (1.11.1-r4) | |
| Stream | libssh2 | Fixed (1.11.1-r5) |
References
- https://github.com/bikini/exploitarium/tree/main/libssh2-publickey-list-calc-poc
- https://github.com/libssh2/libssh2/blob/master/src/publickey.c
- https://www.vulncheck.com/advisories/libssh2-free-of-uninitialized-pointer-in-publickey-list-cleanup
- https://github.com/libssh2/libssh2/commit/a9758da45a52bc8c630ec9493804d0c6ea30b24a