CVE-2025-59058 is a medium-severity (CVSS 5.9) CWE-208 vulnerability in httpsig. A fix is available for httpsig — see the affected versions and patch details below.
httpsig-rs's HMAC verification is vulnerable to timing attack
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2025-59058.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
httpsigReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects crates.io packages — download data is not available via public APIs for these ecosystems.
Description
Summary
HMAC signature comparison is not timing-safe and is vulnerable to timing attacks.
Details
SharedKey::sign() returns a Vec<u8> which has a non-constant-time equality implementation.
Hmac::finalize() returns a constant-time wrapper (CtOutput) which was discarded. Alternatively, Hmac has a constant-time verify() method.
The problem reported here is due to the following lines in SharedKey::sign() of the previous code:
let mut mac = HmacSha256::new_from_slice(key).unwrap();
mac.update(data);
Ok(mac.finalize().into_bytes().to_vec())
and the merged update changes the third line to directly verify with verify_slice.
Impact
Anyone who uses HS256 signature verification is vulnerably to Timing Attack that allows the attacker to forge a signature.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | httpsig | all versions | 0.0.19cargo update -p httpsig --precise 0.0.19 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for httpsig, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update httpsig to 0.0.19 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-59058 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
Frequently Asked Questions
Is CVE-2025-59058 in your dependencies?
Find it across crates.io, including transitive dependencies.