ruby-jwt: Empty-key HMAC bypass; cross-language sibling of CVE-2026-44351
Published Jul 14, 2026 · Updated Nov 3, 2026
Original summary
Normalized public record · Updated Nov 3, 2026
ruby-jwt: Empty-key HMAC bypass; cross-language sibling of CVE-2026-44351
Publisher and source text is retained separately from QFinch interpretation.
QFinch assessment
`JWT.decode(token, '', true, algorithm: 'HS256')` accepts an attacker-forged token. `OpenSSL::HMAC.digest('SHA256', '', payload)` returns a valid digest under an empty key, and no `raise InvalidKeyError if key.empty?` precondition exists in the HMAC algorithm.
Evidence: public source recordsAffected products
| Affected package, product or range | Fix status |
|---|---|
| Consult the referenced vendor advisory for affected versions. | Consult source advisory |
Matching a version is only one part of assessing exposure. QFinch has not assessed your environment on this public page.
Remediation
Apply the vendor-supported fixed release or mitigation, then verify the affected component is no longer reachable.
- Confirm the affected product and reachable code path exist in your environment.
- Apply the vendor-supported patch or mitigation from the primary advisory.
- Rescan the exact deployed revision and retain verification evidence.
Evidence coverage
- SSVC priority
- MEDIUM
- Confidence
- Not available
- Aliases
- None reported
Scores appear only when corresponding evidence exists. Missing data is never interpreted as zero risk.
Sources and record history
- Patch commit ↗
- Patch commit ↗
- Source repository ↗
- Source repository ↗
- Security advisory ↗
- lists.debian.org ↗
Record history
Published Jul 14, 2026 · Last refreshed Nov 3, 2026