CVE-2026-120459
python-jose through 3.5.0 contains an authentication bypass vulnerability that allows…
- Risk score
- 59/100
- CVSS
- 7.4 v3.1
- Published
- 2 Nov 2026
Open in the live forecast Today's forecast
What to know
- What it is
- python-jose through 3.5.0 contains an authentication bypass vulnerability that allows unauthenticated attackers to forge JWTs because HMACKey and CryptographyHMACKey accept zero-length HMAC secrets. When an application's HS256/HS384/HS512 verification key resolves to empty, such as an oct JWK with empty k, attackers c…
- Affected
- See advisory
- Fix
- Apply the vendor's security update; see the linked advisory.
- Exploitation
- No known exploitation
Why it is Yellow
- CVSS 7.4 high
- Remotely exploitable without logging in
- On your watchlist: python
References
- https://github.com/mpdavis/python-jose/blob/3.5.0/jose/backends/cryptography_backend.py
- https://github.com/mpdavis/python-jose/blob/3.5.0/jose/backends/native.py
- https://github.com/mpdavis/python-jose/issues/398
- https://www.vulncheck.com/advisories/python-jose-through-3.5.0-authentication-bypass-via-empty-hmac-key
Original description
python-jose through 3.5.0 contains an authentication bypass vulnerability that allows unauthenticated attackers to forge JWTs because HMACKey and CryptographyHMACKey accept zero-length HMAC secrets. When an application's HS256/HS384/HS512 verification key resolves to empty, such as an oct JWK with empty k, attackers can forge tokens with arbitrary claims that jwt.decode accepts.
Last activity 2 Nov 2026. Patch Forecast updates every hour.