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PatchSiren cyber security CVE debrief

CVE-2016-7037 Emarref CVE debrief

CVE-2016-7037 describes a signature-verification weakness in the jwt library’s symmetric verification path. The affected verify function in Encryption/Symmetric.php compares hashes without a timing-safe method, which can leak information through response timing and enable signature spoofing. NVD rates the issue HIGH, with network access, no privileges, and integrity impact as the primary concern.

Vendor
Emarref
Product
CVE-2016-7037
CVSS
HIGH 7.5
CISA KEV
Not listed in stored evidence
Original CVE published
2017-01-23
Original CVE updated
2026-05-13
Advisory published
2017-01-23
Advisory updated
2026-05-13

Who should care

Teams that use emarref/jwt, especially deployments running version 1.0.2 or earlier, should treat this as an authentication-integrity issue. Application owners, platform teams, and maintainers of services that accept JWTs for login or API authorization should prioritize it.

Technical summary

NVD records the vulnerability as affecting emarref/jwt versions up to and including 1.0.2, with the fix released in 1.0.3. The issue is a missing timing-safe hash comparison in the verify function in Encryption/Symmetric.php. NVD maps the weakness to CWE-361 and assigns CVSS 3.0 vector AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N, indicating a remotely reachable integrity impact without required authentication.

Defensive priority

High. This is an authentication and token-integrity problem that can allow forged signatures if an attacker can exploit the timing side channel. Because the vulnerable path is exposed through normal JWT verification, remediation should be prioritized for any internet-facing or broadly accessible service using the affected library.

Recommended defensive actions

  • Upgrade emarref/jwt to version 1.0.3 or later, which is the referenced fixed release.
  • Confirm all lockfiles, vendor bundles, and container images no longer include version 1.0.2 or earlier.
  • Review services that rely on JWT verification and validate that they are loading the patched library path.
  • If there is any concern that the flaw may have been abused, review authentication logs and reissue sensitive tokens as part of incident response.
  • Add dependency scanning or release checks so future builds block vulnerable jwt versions.

Evidence notes

The supplied NVD record states that the verify function in Encryption/Symmetric.php in Malcolm Fell jwt before 1.0.3 does not use a timing-safe function for hash comparison, enabling signature spoofing via timing attack. The same record lists vulnerable versions through 1.0.2, the CVSS 3.0 vector AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N, and CWE-361. References in the source corpus point to the patch pull request and the 1.0.3 release tag, supporting the remediation boundary. Published date used here is 2017-01-23 per the supplied CVE timeline.

Official resources

Publicly recorded by NVD on 2017-01-23 and later modified on 2026-05-13. No CISA KEV entry is present in the supplied data.