Medium (5.9). EPSS 0.3% chance of exploitation in the next 30 days. Fixed in httpsig 0.0.19.
httpsig-rs is a Rust implementation of IETF RFC 9421 http message signatures. Prior to version 0.0.19, the HMAC signature comparison is not timing-safe. This makes anyone who uses HS256 signature verification vulnerable to a timing attack that allows the attacker to forge a signature. Version 0.0.19 fixes the issue.
Severity
CVSS 3.1
5.9 medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
EPSS
0.3% chance of exploitation in the next 30 days; higher than 20% of CVEs (scores of 2026-10-31)