Unrated severityNVD Advisory· Published Jun 17, 2026· Updated Jun 18, 2026
libssh2 - Out-of-Bounds Write via Unchecked packet_length in transport.c
CVE-2026-55200
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.
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
Affected products
4- osv-coords3 versionspkg:apk/chainguard/libssh2-docpkg:apk/wolfi/libssh2-docpkg:rpm/opensuse/libssh2_org&distro=openSUSE%20Tumbleweed
< 1.11.1-r6+ 2 more
- (no CPE)range: < 1.11.1-r6
- (no CPE)range: < 1.11.1-r6
- (no CPE)range: < 1.11.1-3.1
Patches
Vulnerability mechanics
References
3- github.com/libssh2/libssh2/commit/97acf3dfda80c91c3a8c9f2372546301d4a1a7a8mitrepatch
- www.vulncheck.com/advisories/libssh2-out-of-bounds-write-via-unchecked-packet-length-in-transport-cmitrethird-party-advisory
- github.com/libssh2/libssh2/pull/2052mitreissue-tracking
News mentions
6- Researcher Behind 'Exploitarium' Explains Release of Undisclosed Zero-Day ExploitsInfosecurity Magazine · Jul 2, 2026
- Anonymous researcher drops 0-day 'exploitarium' repoThe Register Security · Jun 29, 2026
- ⚡ Weekly Recap: Linux Kernel Flaws, AI Malware Tricks, Turla Backdoor, Infostealers and MoreThe Hacker News · Jun 29, 2026
- Public PoC Released for Critical libssh2 CVE-2026-55200 Client-Side SSH FlawThe Hacker News · Jun 29, 2026
- PoC Exploit Released for libssh2 Remote Code Execution VulnerabilityCyber Security News · Jun 24, 2026
- Critical libssh2 Vulnerability Allows Attackers to Execute Remote Code Via Malicious SSH packetsCyber Security News · Jun 23, 2026