CVE-2026-55200 The advisory has been revoked - it doesn't affect any version of package libssh2 (opens in a new tab)
Threat Intelligence
Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-CENTOS7-LIBSSH2-17443101
- published24 Jun 2026
- disclosed17 Jun 2026
Introduced: 17 Jun 2026
CVE-2026-55200 (opens in a new tab)Amendment
The Centos security team deemed this advisory irrelevant for Centos:7.
NVD Description
Note: Versions mentioned in the description apply only to the upstream libssh2 package and not the libssh2 package as distributed by Centos.
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
- https://access.redhat.com/security/cve/CVE-2026-55200
- 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
- https://github.com/0xBlackash/CVE-2026-55200