fast-jwt provides fast JSON Web Token (JWT) implementation. Prior to 6.3.1, fast-jwt createVerifier accepts an unsigned JWT when key is an empty string or null and algorithms is a non-empty allowlist. Falsy synchronous keys bypass prepareKeyOrSecret, allowedAlgorithms remains active, hasKey is false, and the empty signature avoids the verifySignature gate. An attacker can therefore submit a token containing arbitrary claims without possessing a signing key, resulting in authentication or authorization bypass. Claim validators still run, and non-empty keys, an empty key without algorithms, and the async key resolver path do not have this behavior. This issue is fixed in version 6.3.1.
CVE-2026-107720
HIGHPre-NVD 7.47.4Trending — 3 sources updated this weekElevated
EchelonGraph scoreLOW confidence
This high-severity CVE scores 7.4 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit-prediction score not yet available (the EPSS model rescores nightly; freshly-published CVEs typically appear within 48 hours). 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: secondary
7.4EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
- High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.3%CVSS: 7.4Exploit: Elevated riskExposed services: Not assessed
A fix is available — apply it.
- CVSS v3
- 7.4
- EG Score
- 7.4HIGHlow confidence
- EG Risk
- 49EG Risk 49/100CISA SSVC
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity74% × 45%Exploitation40% × 40%Automatability0% × 15%CISA SSVC: Track at low, Track* at medium and Attend at high mission impact.Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high. - EPSS PROB
- 0.3%
- EPSS %ILE
- 15th
- KEV
- Not listed
CISA SSVCTrack at low, Track* at medium and Attend at high mission impact.
A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table
Published
October 8, 2026
Last Modified
October 9, 2026
Advisory Details (4)
Auto-updated Oct 8, 2026🔬 Proof of concept available. Patch available. Sources: github, github_pr, github_commit, github_release.
github_release Patch Available
v6.3.1
Patch available: nearform/fast-jwt v6.3.1
https://github.com/nearform/fast-jwt/releases/tag/v6.3.1github_commit Patch Available
commit e22a151e83bf (nearform/fast-jwt)
Patch available: nearform/fast-jwt v6.3.1 (contains commit e22a151e83bf)
https://github.com/nearform/fast-jwt/commit/e22a151e83bf6d5e54e281216982d204d5665534github_pr Patch Available
fix: require a key unless the only allowed algorithm is "none" (GHSA-8wpc-h4q6-8fxv)
Patch available: nearform/fast-jwt v6.3.1 (PR #649 merged 2026-07-30)
https://github.com/nearform/fast-jwt/pull/649githubMentions a patch (unverified)🟡 PoC Available
createVerifier accepts unsigned JWTs when key is '' or null and algorithms is explicitly set · Advisory · nearform/fast-jwt · GitHub
https://github.com/nearform/fast-jwt/security/advisories/GHSA-8wpc-h4q6-8fxvVendor Advisories for CVE-2026-107720(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)
npm(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| fast-jwt | — |
| — |
Weakness Classification(2)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 6× in last 7d / 6× 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.
- 2026-10-09 20:06 UTCEPSS rescore
- 2026-10-09 15:34 UTCEG score recompute
- 2026-10-09 14:52 UTCEG score recompute
- 2026-10-08 22:21 UTCEG score recompute
- 2026-10-08 21:53 UTCEG score recompute
- 2026-10-08 21:53 UTCMITRE cvelistV5first tracked
Related CVEs(same product + same CWE)
Same product
10 shownnpm:fast-jwt
Frequently asked(5)
What is CVE-2026-107720?
CVE-2026-107720 is a high vulnerability published on October 8, 2026. fast-jwt provides fast JSON Web Token (JWT) implementation. Prior to 6.3.1, fast-jwt createVerifier accepts an unsigned JWT when key is an empty string or null and algorithms is a non-empty allowlist. Falsy synchronous keys bypass prepareKeyOrSecret, allowedAlgorithms remains active, hasKey is…
When was CVE-2026-107720 disclosed?
CVE-2026-107720 was first published on October 8, 2026, with the most recent update on October 9, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-107720 actively exploited?
CVE-2026-107720 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.3% probability of exploitation in the next 30 days (15th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-107720?
CVE-2026-107720 has a CVSS base score of 7.4 (a secondary CVSS source that NVD displays; NVD's own analysis pending). The EG score is currently aggregating — additional source signals are being incorporated as they become available..
How do I remediate CVE-2026-107720?
A fix for CVE-2026-107720 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-107720 are linked in the Vendor Advisories panel on this page.
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-107720
Is Your Infrastructure Affected by CVE-2026-107720?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.