python-jose through 3.5.0 contains an authentication bypass vulnerability that allows unauthenticated attackers to
Source GCVE Database
Not known to be exploited · CVSS 9.1 Critical · patch available : patch python-jose as a priority.
Data as of 2 Nov 2026, 16:28 UTC
Thin evidence
One scorer or none| CNA (VulnCheck) | CVSS 4.0 | 9.1 |
|---|---|---|
| CNA (VulnCheck) | CVSS 3.1 | 7.4 |
- Patch
- Available
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 2 Nov 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2 Nov 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| mpdavispython-jose | Affected
| Fixed in– |
PyPIpython-josepkg:pypi/python-joseOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
If you cannot patch yet, ensure that HMAC secrets are never zero-length and validate JWT verification keys properly to prevent empty keys from being used.
Description
python-jose versions through 3.5.0 have an authentication bypass vulnerability due to acceptance of zero-length HMAC secrets. This flaw allows unauthenticated attackers to forge JSON Web Tokens (JWTs) with arbitrary claims when the verification key is empty, compromising token integrity and authentication.
References
- nvd.nist.gov/vuln/detail/CVE-2026-120459 (opens in a new tab)
- github.com/mpdavis/python-jose/issues/398 (opens in a new tab)
- github.com/mpdavis/python-jose/blob/3.5.0/jose/backends/cryptography_backend.py (opens in a new tab)
- github.com/mpdavis/python-jose/blob/3.5.0/jose/backends/native.py (opens in a new tab)
- vulncheck.com/advisories/python-jose-through-3.5.0-authentication-bypass-via-empty-hmac-key (opens in a new tab)