CVE-2026-58051

high

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.

References

https://www.vulncheck.com/advisories/libssh2-free-of-uninitialized-pointer-in-publickey-list-cleanup

https://github.com/bikini/exploitarium/tree/main/libssh2-publickey-list-calc-poc

https://github.com/libssh2/libssh2/blob/master/src/publickey.c

Details

Source: Mitre, NVD

Published: 2026-06-28

Updated: 2026-06-30

Risk Information

CVSS v2

Base Score: 6.1

Vector: CVSS2#AV:N/AC:H/Au:N/C:N/I:P/A:C

Severity: Medium

CVSS v3

Base Score: 6.5

Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H

Severity: Medium

CVSS v4

Base Score: 8.3

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

Severity: High

EPSS

EPSS: 0.0028