CVE-2026-58050

libssh2 through 1.11.1 reads an attacker-controlled 32-bit attribute count from a publickey-subsystem response and uses it in the allocation num_attrs * sizeof(libssh2_publickey_attribute) without bounds checking, so on 32-bit platforms the multiplication overflows to an undersized buffer. A malicious SSH server can then drive the attribute-parsing loop to write past the allocation, causing a heap buffer overflow in a connecting libssh2 client.

• libssh2 1.11.1-6 (bug https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1144415) [trixie] - libssh2 (Minor issue; can be fixed via point release) https://github.com/bikini/exploitarium/tree/main/libssh2-publickey-list-calc-poc https://github.com/libssh2/libssh2/pull/2128 Fixed by: https://github.com/libssh2/libssh2/commit/34497525929b9a47f03dfb81887ac896202b7e12