CVE-2026-55200: fallo crítico en libssh2
libssh2 - Out-of-Bounds Write via Unchecked packet_length in transport.c
Publicada el · Actualizada el
Aviso por correo cuando entre en el KEV, tenga PoC pública o suba de nota.
48Vexday Risk Score
Sin señal de explotación. Ella tiene prueba de concepto pública.
ssvc Attendcvss 9.2epss 3.9%
de la publicación al arma6 días
Publicada en NVD17 jun
1ª PoC+6d
libssh2 1.11.1, fixed in commit 97acf3d, 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
Productos afectados
libssh2 · libssh2PoCs públicas encontradas — 5
githubgithub.com/0xBlackash/CVE-2026-55200★ 10githubgithub.com/xd20111/CVE-2026-55200★ 4githubgithub.com/kaleth4/CVE-2026-55200★ 0cve_referencegithub.com/bikini/exploitarium/tree/main/libssh2-cve-2026-55200-pocno verificadocve_referenceweb.archive.org/web/20260623211210/https://github.com/bikini/exploitarium/tree/main/libssh2-cve-2026-55200-pocno verificado⚠ Recursos públicos, para evaluar la exposición de sistemas que controlas o estás autorizado a probar. Prueba solo con autorización.
CVEs relacionadas — libssh2
En el mismo producto, de las más peligrosas a las menos.
CVE-2026-55199HIGHlibssh2 - Pre-Authentication DoS via SSH_MSG_EXT_INFO HandlerEPSS 0.9%CVE-2025-15661HIGHlibssh2 - Heap Buffer Over-read via sftp_symlink() in sftp.cEPSS 0.6%CVE-2026-66033HIGHlibssh2 Integer Underflow DoS via AES-GCM Cipher NegotiationEPSS 0.6%CVE-2026-66035HIGHlibssh2 Heap Buffer Overflow via ETM Cipher NegotiationEPSS 0.5%CVE-2026-66032HIGHlibssh2 Double-Free Heap Corruption via sftp_open()EPSS 0.4%CVE-2026-58050HIGHlibssh2 - Integer Overflow in publickey Subsystem Attribute AllocationEPSS 0.4%
Referencias
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