CVE-2026-55200
High · CVSS 8.1libssh2 — out-of-bounds write heap corruption RCE
- CVSS
- 8.1
- nvd
- EPSS
- —
- KEV
- No
- Class
- oss containerizable
- CWE-680
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.
Search profile — drives PoC discovery
Symbols ssh2_transport_readpacket_lengthtransport.c97acf3dfda80c91c3a8c9f2372546301d4a1a7a87acf3df
Keywords CVE-2026-55200libssh2out-of-bounds writepacket_lengthssh2_transport_readheap corruptionlibssh2 RCElibssh2-cve-2026-55200-pocexploitariumlibssh2 1.11.1transport.c libssh2unchecked packet length
Versions: through 1.11.1 (fixed in commit 7acf3df / 97acf3dfda80c91c3a8c9f2372546301d4a1a7a8)
Ranked PoCs (4) — best first
Heuristic ranking — not yet expert-vetted. Scored on structure + provenance, not execution.
- ★ 0
- ★ 10
- ★ 2
- ★ 0
Recall-favoring discovery; ranking by the Stage-4 scorer (Adam's rubric). Scanner/aggregator repos are hidden.
References
- https://github.com/libssh2/libssh2/commit/97acf3dfda80c91c3a8c9f2372546301d4a1a7a8
- https://github.com/libssh2/libssh2/pull/2052
- https://www.vulncheck.com/advisories/libssh2-out-of-bounds-write-via-unchecked-packet-length-in-transport-c
- https://web.archive.org/web/20260623211210/https://github.com/bikini/exploitarium/tree/main/libssh2-cve-2026-55200-poc
Status: enriched · ingested 2026-07-15T00:00:20.000Z · profiled 2026-07-15T00:30:20.000Z