Affected: libssh2

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.

Affected: Ubuntu:24.04:LTS: libssh2, Ubuntu:26.04:LTS: libssh2

It was discovered that libssh2 incorrectly handled certain publickey subsystem attributes. A remote attacker controlling a malicious SSH server could use this issue to cause a denial of service or possibly execute arbitrary code. (CVE-2026-58050)

It was discovered that libssh2 did not properly initialize publickey list entries before parsing. A remote attacker controlling a malicious SSH server could use this issue to cause a denial of service or possibly execute arbitrary code. (CVE-2026-58051)