Infinite loop in libssh2 - CVE-2026-55199
Published: July 1, 2026
Vulnerability identifier: #VU136048
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-55199
CWE-ID: CWE-835
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: libssh2.org
Affected software:
libssh2
libssh2
Detailed vulnerability description
The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.
The vulnerability exists due to infinite loop within the SSH_MSG_EXT_INFO handler in src/packet.c. A remote attacker can consume all available system resources and cause denial of service conditions.
How to mitigate CVE-2026-55199
Install updates from vendor's repository.