CVE-2026-26275

Workarounds

There is no reliable workaround without upgrading. Users who cannot immediately upgrade should avoid relying solely on Digest verification for message integrity and ensure that full HTTP message signature verification is enforced at the application layer.

References

• PR: https://github.com/junkurihara/httpsig-rs/pull/14
• Follow-up hardening and test additions: https://github.com/junkurihara/httpsig-rs/pull/15

An issue was discovered in httpsig-hyper where Digest header verification could incorrectly succeed due to misuse of Rust's matches! macro. Specifically, the comparison:

if matches!(digest, _expected_digest)

treated _expected_digest as a pattern binding rather than a value comparison, resulting in unconditional success of the match expression.

As a consequence, digest verification could incorrectly return success even when the computed digest did not match the expected value.

Applications relying on Digest verification as part of HTTP message signature validation may therefore fail to detect message body modification. The severity depends on how the library is integrated and whether additional signature validation layers are enforced.

CVE-2026-26275 has a CVSS score of 7.5 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.0.23); upgrading removes the vulnerable code path.

Kodem intelligence

This issue has been fixed in:

• httpsig-hyper >= 0.0.23

The fix replaces the incorrect matches! usage with proper value comparison and additionally introduces constant-time comparison for digest verification as defense-in-depth.

Regression tests have also been added to prevent reintroduction of this issue. Users are strongly advised to upgrade to the patched version.

1. What is CVE-2026-26275? CVE-2026-26275 is a high-severity security vulnerability in httpsig-hyper (rust), affecting versions < 0.0.23. It is fixed in 0.0.23.
2. How severe is CVE-2026-26275? CVE-2026-26275 has a CVSS score of 7.5 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of httpsig-hyper are affected by CVE-2026-26275? httpsig-hyper (rust) versions < 0.0.23 is affected.
4. Is there a fix for CVE-2026-26275? Yes. CVE-2026-26275 is fixed in 0.0.23. Upgrade to this version or later.
5. Is CVE-2026-26275 exploitable, and should I be worried? Whether CVE-2026-26275 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-26275 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-26275? Upgrade httpsig-hyper to 0.0.23 or later.