CVE-2026-55200
Published: June 20, 2026Last modified: July 17, 2026
Description
libssh2 through 1.11.1, fixed in commit 7acf3df contains an out-of-bounds write vulnerability in ssh2_transport_read() that fails to enforce upper bounds on packet_length field. Remote attackers can send crafted SSH packets with excessively large packet_length values to corrupt heap memory and achieve remote code execution.
Severity score breakdown
| Parameter | Value |
|---|---|
| Base score | 8.3 |
| Attack Vector | NETWORK |
| Attack complexity | LOW |
| Privileges required | NONE |
| User interaction | REQUIRED |
| Scope | UNCHANGED |
| Confidentiality | HIGH |
| Integrity impact | HIGH |
| Availability impact | LOW |
| Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:L |
Status
| Product | Release | Package | Status |
|---|---|---|---|
| Alpaquita Linux | 23 LTS | libssh2 | Fixed (1.11.1-r3) |
| 25 LTS | libssh2 | Fixed (1.11.1-r2) | |
| Stream | libssh2 | Fixed (1.11.1-r3) | |
| rust | Fixed (1.96.1-r0) |
References
- https://github.com/bikini/exploitarium/tree/main/libssh2-cve-2026-55200-poc
- https://github.com/libssh2/libssh2/commit/97acf3dfda80c91c3a8c9f2372546301d4a1a7a8
- https://github.com/libssh2/libssh2/pull/2052
- https://web.archive.org/web/20260623211210/https://github.com/bikini/exploitarium/tree/main/libssh2-cve-2026-55200-poc
- https://www.vulncheck.com/advisories/libssh2-out-of-bounds-write-via-unchecked-packet-length-in-transport-c