CVE-2026-55200

CRITICAL9.2

libssh2 - Out-of-Bounds Write via Unchecked packet_length in transport.c

Published Jun 17, 2026

Modified 2 days ago

Details

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.

References

DETECTION

https://github.com/bikini/exploitarium/tree/main/libssh2-cve-2026-55200-poc

FIX

https://github.com/libssh2/libssh2/commit/97acf3dfda80c91c3a8c9f2372546301d4a1a7a8

WEB

https://github.com/libssh2/libssh2/pull/2052

ADVISORY

https://www.cve.org/CVERecord?id=CVE-2026-55200

ADVISORY

https://www.vulncheck.com/advisories/libssh2-out-of-bounds-write-via-unchecked-packet-length-in-transport-c

CVSS Analysis