CVE-2026-58051
Publication date 28 June 2026
Last updated 7 July 2026
Ubuntu priority
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.
Status
| Package | Ubuntu Release | Status |
|---|---|---|
| libssh2 | 26.04 LTS resolute |
Needs evaluation
|
| 25.10 questing |
Needs evaluation
|
|
| 24.04 LTS noble |
Needs evaluation
|
|
| 22.04 LTS jammy |
Needs evaluation
|
|
| 20.04 LTS focal |
Needs evaluation
|
|
| 18.04 LTS bionic |
Needs evaluation
|
|
| 14.04 LTS trusty |
Needs evaluation
|
Severity score breakdown
CVSS version:
Base score
8.3 · High
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
Base score
6.5 · Medium
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H
References
Other references
- https://www.cve.org/CVERecord?id=CVE-2026-58051
- 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/pull/2202