ruby-jwt is a Ruby implementation of the RFC 7519 OAuth JSON Web Token standard. Prior to 2.10.3 and 3.2.0, JWT.decode(token, '', true, algorithm: 'HS256') accepts an attacker-forged token because OpenSSL::HMAC.digest('SHA256', '', payload) returns a valid digest under an empty key and no empty-key precondition exists in the HMAC algorithm. The same path is reached when a keyfinder block or key_finder: argument returns an empty string, nil, or an array containing nil for an unknown key, affecting HS256, HS384, and HS512 verification through JWT.decode and JWT::EncodedToken#verify_signature!. This issue is fixed in versions 2.10.3 and 3.2.0.
CVE-2026-45363
CRITICALPre-NVD 9.17.4
EchelonGraph scoreLOW confidence
This high-severity CVE scores 7.4 under the CNA's CVSS (NVD's own analysis pending). EPSS exploit probability: 0.0%, top 95% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
Triggered by: NVD CVSS baseline
Sources: cna:github_m, epss
9.1
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
- High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 9.1Exploit: NoneExposed: 0
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 9.1
- EG Score
- 7.4(low)
- EG Risk
- —
- EPSS
- 15.4%
- KEV
- Not listed
Published
May 18, 2026
Last Modified
July 15, 2026
Advisory Details (5)
Auto-updated Jul 14, 2026Patch available. Sources: github, github_commit, github_release.
github_release Patch Available
jwt-3.2.0
Patch available: jwt/ruby-jwt v3.2.0
https://github.com/jwt/ruby-jwt/releases/tag/v3.2.0github_release Patch Available
jwt-2.10.3
Patch available: jwt/ruby-jwt v2.10.3
https://github.com/jwt/ruby-jwt/releases/tag/v2.10.3github_commit Patch Available
commit db560b769a07 (jwt/ruby-jwt)
Patch available: jwt/ruby-jwt v3.2.0 (contains commit db560b769a07)
https://github.com/jwt/ruby-jwt/commit/db560b769a07bd9724e77ff505011ac01872106fgithub_commit Patch Available
commit 9820020869ad (jwt/ruby-jwt)
Patch available: jwt/ruby-jwt v2.10.3 (contains commit 9820020869ad)
https://github.com/jwt/ruby-jwt/commit/9820020869ad147b941e49d96ab8beba35532964github Patch Available
Empty-key HMAC bypass; cross-language sibling of CVE-2026-44351 · Advisory · jwt/ruby-jwt · GitHub
https://github.com/jwt/ruby-jwt/security/advisories/GHSA-c32j-vqhx-rx3xVendor Advisories for CVE-2026-45363(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Affected Packages
(1 across 1 ecosystem)
RubyGems(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| jwt | 0.1.1 ... 2.9.3 (49 versions) | 2.10.3 | — |
Weakness Classification(3)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 7× in last 7d / 9× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-07-22 14:08 UTCEPSS rescore
- 2026-07-21 15:24 UTCEPSS rescore
- 2026-07-20 17:08 UTCEPSS rescore
- 2026-07-19 02:29 UTCEPSS rescore
- 2026-07-18 10:04 UTCEPSS rescore
- 2026-07-18 00:29 UTCOSV refresh
- 2026-07-16 17:03 UTCEPSS rescore
- 2026-07-15 16:57 UTCEPSS rescore
- 2026-07-14 21:35 UTCMITRE cvelistV5CVSS v3 → 9.1 · severity → CRITICAL
- 2026-06-14 23:18 UTCEPSS rescore
- 2026-06-13 23:00 UTCEPSS rescore
- 2026-06-12 23:12 UTCEPSS rescore
- 2026-05-24 06:16 UTCEG score recompute
Frequently asked(5)
What is CVE-2026-45363?
CVE-2026-45363 is a critical vulnerability published on May 18, 2026. ruby-jwt is a Ruby implementation of the RFC 7519 OAuth JSON Web Token standard. Prior to 2.10.3 and 3.2.0, JWT.decode(token, '', true, algorithm: 'HS256') accepts an attacker-forged token because OpenSSL::HMAC.digest('SHA256', '', payload) returns a valid digest under an empty key and no empty-key…
When was CVE-2026-45363 disclosed?
CVE-2026-45363 was first published in the National Vulnerability Database on May 18, 2026, with the most recent update on July 15, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-45363 actively exploited?
CVE-2026-45363 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 15.4% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-45363?
CVE-2026-45363 has a CVSS v3 base score of 9.1 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 7.4. The EG score is currently aggregating — additional source signals are being incorporated as they become available..
How do I remediate CVE-2026-45363?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-45363, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-45363
Is Your Infrastructure Affected by CVE-2026-45363?
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