CVE-2026-58050

Description

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.

Severity (CVSS)

Weaknesses

• CWE-190 — Integer Overflow or Wraparound

Affected products

References

• https://github.com/bikini/exploitarium/tree/main/libssh2-publickey-list-calc-poc (exploit third-party-advisory)
• https://github.com/libssh2/libssh2/blob/master/src/publickey.c (product)
• https://www.vulncheck.com/advisories/libssh2-integer-overflow-in-publickey-subsystem-attribute-allocation (third-party-advisory)