CVE-2026-58050: libssh2 Integer Overflow or Wraparound

Vulnerability summary

CVE-2026-58050 is a high (CVSS 8.3) Integer Overflow or Wraparound vulnerability in libssh2. EPSS estimates a 0.44% chance of exploitation in the next 30 days, higher than 37.3% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 28-06-2026
   PublishedVulnerability first disclosed.
2. 29-06-2026
   Last modifiedVulnerability information updated.

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.

• CWE-190Integer Overflow or WraparoundThe product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.