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.

CVSS v4.0

8.3 HIGHCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CVSS v3.1

6.5 MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H

EPSS

0.28% chance of exploitation in the next 30 days, 20th percentile

Published

2026-06-28

Updated

2026-06-29

Proof-of-concept exploits (1)

• bikini/exploitarium/tree/main/libssh2-publickey-list-calc-poc

References

• CVE Record
• NVD entry

Related

• CVE-2026-58049
• CVE-2026-58050
• CVE-2026-58052
• CVE-2026-58053
• CVE-2026-58055
• CVE-2026-58056