CVE-2026-58050
Published: July 1, 2026Last modified: August 24, 2026
Description
libssh2 through 1.11.1 reads an attacker-controlled 32-bit attribute count from a publickey-subsystem response and uses it in the allocation num_attrs * sizeof(libssh2_publickey_attribute) without bounds checking, so on 32-bit platforms the multiplication overflows to an undersized buffer. A malicious SSH server can then drive the attribute-parsing loop to write past the allocation, causing a heap buffer overflow in a connecting libssh2 client.
Severity score breakdown
| Parameter | Value |
|---|---|
| Base score | 7.5 |
| Attack Vector | NETWORK |
| Attack complexity | LOW |
| Privileges required | NONE |
| User interaction | NONE |
| Scope | UNCHANGED |
| Confidentiality | NONE |
| Integrity impact | NONE |
| Availability impact | HIGH |
| Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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-integer-overflow-in-publickey-subsystem-attribute-allocation
- https://github.com/libssh2/libssh2/commit/34497525929b9a47f03dfb81887ac896202b7e12