libssh2 - Out-of-Bounds Write via Unchecked packet_length in transport.c
48Vexday Risk Score
No sign of exploitation. It has a public proof of concept.
ssvc Attendcvss 9.2epss 2.0%
from disclosure to weapon6 days
Published on NVDJun 17
1st PoC+6d
exploitation probability
2.0%top 21% of all CVEs
observed exploitation
nono source reports it
5 public exploit(s)
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.
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Affected products
libssh2 · libssh2public PoCs found — 5
githubgithub.com/0xBlackash/CVE-2026-55200★ 10githubgithub.com/xd20111/CVE-2026-55200★ 3githubgithub.com/kaleth4/CVE-2026-55200★ 0cve_referencegithub.com/bikini/exploitarium/tree/main/libssh2-cve-2026-55200-pocunverifiedcve_referenceweb.archive.org/web/20260623211210/https://github.com/bikini/exploitarium/tree/main/libssh2-cve-2026-55200-pocunverified⚠ Public resources, to assess the exposure of systems you control or are authorized to test. Test only with authorization.
References
https://github.com/libssh2/libssh2/commit/97acf3dfda80c91c3a8c9f2372546301d4a1a7a8https://github.com/libssh2/libssh2/pull/2052https://web.archive.org/web/20260623211210/https://github.com/bikini/exploitarium/tree/main/libssh2-cve-2026-55200-pochttps://www.vulncheck.com/advisories/libssh2-out-of-bounds-write-via-unchecked-packet-length-in-transport-c