libssh Cert Auth Loop Denial (CVE-2026-59849)
CVE-2026-59849 Published on July 21, 2026
Libssh: libssh: denial of service via automatic certificate authentication loop
A flaw was found in libssh. Logic errors in automatic certificate-based public key authentication can cause libssh clients to loop indefinitely when configured certificates are missing or repeatedly rejected by a server, leading to denial of service.
Vulnerability Analysis
CVE-2026-59849 can be exploited with network access, and requires small amount of user privileges. This vulnerability is consided to have a high level of attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a small impact on availability.
Timeline
Reported to Red Hat.
Made public. 83 days later.
Weakness Type
What is an Infinite Loop Vulnerability?
The program contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop. If the loop can be influenced by an attacker, this weakness could allow attackers to consume excessive resources such as CPU or memory.
CVE-2026-59849 has been classified to as an Infinite Loop vulnerability or weakness.
Products Associated with CVE-2026-59849
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