Description
A flaw was found in libssh's handling of key exchange (KEX) processes when a client repeatedly sends incorrect KEX guesses. The library fails to free memory during these rekey operations, which can gradually exhaust system memory. This issue can lead to crashes on the client side, particularly when using libgcrypt, which impacts application stability and availability.
Problem types
Missing Release of Memory after Effective Lifetime
Product status
0.6.0 (semver) before 0.11.3
Timeline
| 2025-07-28: | Reported to Red Hat. |
| 2025-09-09: | Made public. |
Credits
Red Hat would like to thank Francesco Rollo for reporting this issue.
References
access.redhat.com/security/cve/CVE-2025-8277
bugzilla.redhat.com/show_bug.cgi?id=2383888 (RHBZ#2383888)