01 Record
CVE-2026-107722
fast-jwt: Incomplete patch of CVE-2026-34950: Non-whitespace key-prefix re-enables RSA→HS256 algorithm confusion
CriticalPUBLISHEDCNA: GitHub_M
CNA base score9.8 CVSS v3.xCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
02 Description
fast-jwt: Incomplete patch of CVE-2026-34950: Non-whitespace key-prefix re-enables RSA→HS256 algorithm confusion
03 Exploitation and scoring
- Exploitation
- Public exploit code exists. CISA's assessment records a public proof of concept. That is not a report of exploitation in the wild.
- SSVC decision
- ExploitationpocPublic proof-of-concept exploit code exists. Not a report of exploitation in the wild.
- AutomatableyesAn attacker can reliably automate reconnaissance through exploitation, so this scales.
- Technical ImpacttotalSuccessful exploitation gives total control of the vulnerable component.
- EPSS probability
- 0.35% probability of exploitation activity in the next 30 days.
- EPSS percentile
- Equal to or higher than the score of 29.0% of scored records. A rank, not a probability.
- NVD base score
- 9.8 (CVSS v3.x), scored by the NVD independently of the CNA.
- NVD CVSS vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- NVD analysis status
- Deferred. NVD last modified this record on 2026-10-13.
- Red Hat severity
- No Red Hat rating. Red Hat rates the CVEs that affect its products.
Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.
04 Metadata
- Published
- 2026-10-08 21:49Z20 DAYS AGO
- Last updated
- 2026-10-13 16:26Z15 DAYS AGO
- Reserved
- 2026-10-08
- Assigning CNA
- GitHub_M
- Record state
- PUBLISHED
- Severity
- Critical (CVSS 9.8)
- CNA CVSS vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Weaknesses
- CWE-347Improper Verification of Cryptographic SignatureBase
- Data version
- 5.2
- Document digest
- 0370c9bf187030b4a52981a595425c47fa0993635d5b9faea6fce8fa20026157
05 Affected products
VendorProductVersionsPlatforms
06 References
- github.comhttps://github.com/nearform/fast-jwt/security/advisories/GHSA-ww5h-9m49-7xx4
- github.comhttps://github.com/nearform/fast-jwt/pull/632
- github.comhttps://github.com/nearform/fast-jwt/commit/d96bbc6c5336055a6dbfa318fdbab01197264cfa
- github.comhttps://github.com/nearform/fast-jwt/releases/tag/v6.3.0