CVE-2026-59850 Libssh: libssh: use-after-free via data callbacks on closed channels
Attackers can trigger crashes or potential code execution in libssh by processing data packets on closed channels, affecting systems using this library.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-59850?
CVE-2026-59850 is a medium-severity use after free vulnerability in Redhat Enterprise Linux, published on 21 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
A flaw was found in libssh. If data packets are processed after a channel is closed, channel data callbacks can be invoked after the associated data has already been freed, leading to crashes or possible use-after-free conditions.
Weakness: CWE-416
Which versions are affected by CVE-2026-59850?
It affects 3 products.
Products include Libssh Libssh, Redhat Enterprise Linux, Redhat Hardened Images.
How do I fix CVE-2026-59850?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-59850 being exploited?
There is no known exploitation of CVE-2026-59850 in the wild and no public exploit code.
Other vulnerabilities in Redhat Enterprise Linux
- CVE-2026-59851 Libssh: libssh: authentication bypass via missing gssapi principal check
- CVE-2025-5987 Libssh: invalid return code for chacha20 poly1305 with openssl backend
- CVE-2025-14821 Libssh: libssh: insecure default configuration leads to local man-in-the-middle attacks on windows
- CVE-2012-4560 Memory corruption in n/a
- CVE-2012-4562 Integer overflow in n/a
Sources
Also known as AZL-93258, BELL-CVE-2026-59850, CLSA-2026-1785837198, CLSA-2026-1786092035, CLSA-2026-1786357391, DEBIAN-CVE-2026-59850 and 3 more.