fast-jwt provides fast JSON Web Token (JWT) implementation. From 6.2.0 until 6.3.0, fast-jwt can misclassify RSA public-key text as an HMAC secret when the key has non-whitespace content before its PEM header. In src/crypto.js, performDetectPublicKeyAlgorithms trims whitespace but publicKeyPemMatcher remains start-anchored, so comments, control characters, zero-width characters, or wrapper text can prevent PEM detection and reach the HMAC fallback. An attacker who knows the public key bytes can sign arbitrary HS256 claims with that public material when HS256 is inferred or allowed, resulting in authentication or authorization bypass. An asymmetric-only algorithm allowlist prevents the attack. This issue is fixed in version 6.3.0.
CVE-2026-107722
CRITICALPre-NVD 9.89.8—Trending — 3 sources updated this week
EchelonGraph scoreMEDIUM confidence
This critical-severity CVE scores 9.8 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.3% (17th percentile of EPSS-scored CVEs). 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: epss, secondary
9.8EG
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: 9.8Exploit: None knownExposed services: Not assessed
A fix is available — apply it.
- CVSS v3
- 9.8
- EG Score
- 9.8CRITICALmedium 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 computedSeverity98% × 45%Exploitation0% × 40%Automatability30% × 15%CISA SSVC: Track at low or medium mission impact; Track* or Attend at high (mission-essential systems).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
- 17th
- KEV
- Not listed
CISA SSVCTrack at low or medium mission impact; Track* or Attend at high (mission-essential systems).
A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
Exploitation none (no KEV listing, exploit record or EPSS ≥ 50%) · Automatable unknown (not published for this CVE) · Technical impact total (CVSS ≥ 9.0). 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 8, 2026
Advisory Details (4)
Auto-updated Oct 8, 2026🔬 Proof of concept available. Patch available. Sources: github_commit, github_pr, github_release, github.
githubMentions a patch (unverified)🟡 PoC Available
Incomplete patch of CVE-2026-34950: Non-whitespace key-prefix re-enables RSA→HS256 algorithm confusion in fast-jwt 6.2.x · Advisory · nearform/fast-jwt · GitHub
https://github.com/nearform/fast-jwt/security/advisories/GHSA-ww5h-9m49-7xx4github_release Patch Available
v6.3.0
Patch available: nearform/fast-jwt v6.3.0
https://github.com/nearform/fast-jwt/releases/tag/v6.3.0github_pr Patch Available
fix: reject non-whitespace key prefixes to close RSA→HS256 algorithm confusion (GHSA-ww5h-9m49-7xx4)
Patch available: nearform/fast-jwt v6.3.0 (PR #632 merged 2026-07-27)
https://github.com/nearform/fast-jwt/pull/632github_commit Patch Available
commit d96bbc6c5336 (nearform/fast-jwt)
Patch available: nearform/fast-jwt v6.3.0 (contains commit d96bbc6c5336)
https://github.com/nearform/fast-jwt/commit/d96bbc6c5336055a6dbfa318fdbab01197264cfaVendor Advisories for CVE-2026-107722(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(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 5× in last 7d / 5× 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 20:13 UTCEG score recompute
- 2026-10-09 20:06 UTCEPSS rescore
- 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-2026-107722?
CVE-2026-107722 is a critical vulnerability published on October 8, 2026. fast-jwt provides fast JSON Web Token (JWT) implementation. From 6.2.0 until 6.3.0, fast-jwt can misclassify RSA public-key text as an HMAC secret when the key has non-whitespace content before its PEM header. In src/crypto.js, performDetectPublicKeyAlgorithms trims whitespace but…
When was CVE-2026-107722 disclosed?
CVE-2026-107722 was first published on October 8, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-107722 actively exploited?
CVE-2026-107722 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.3% probability of exploitation in the next 30 days (17th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-107722?
CVE-2026-107722 has a CVSS base score of 9.8 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-107722?
A fix for CVE-2026-107722 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-107722 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-2026-107722
Is Your Infrastructure Affected by CVE-2026-107722?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.