CVE-2026-59842 Libssh: libssh: information disclosure via short gssapi curve25519 public key
A remote unauthenticated attacker can disclose small amounts of server memory via an out-of-bounds heap read during GSSAPI key exchange in libssh.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-59842?
CVE-2026-59842 is a low-severity vulnerability in Redhat Enterprise Linux, published on 21 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
A flaw was found in libssh. During server-side GSSAPI key exchange, a client-supplied Curve25519 public key shorter than the expected length is copied without proper length validation, leading to an out-of-bounds heap read. This could allow a remote unauthenticated attacker to disclose small amounts of server memory.
Weakness: CWE-125
Which versions are affected by CVE-2026-59842?
It affects 11 products.
Products include Libssh Libssh, Redhat Enterprise Linux, Redhat Enterprise Linux for Els, Redhat Enterprise Linux for Eus, Redhat Enterprise Linux for Ibm Z Systems, Redhat Enterprise Linux for Ibm Z Systems Els and 5 more.
How do I fix CVE-2026-59842?
Apply the vendor's patch.
Is CVE-2026-59842 being exploited?
There is no known exploitation of CVE-2026-59842 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 BELL-CVE-2026-59842, DEBIAN-CVE-2026-59842, GHSA-x94w-cg8g-g593, MINI-c4mg-2422-vx22.