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CVE-2026-120459VulnerabilityPublished

python-jose through 3.5.0 contains an authentication bypass vulnerability that allows unauthenticated attackers to

Source GCVE Database

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Authoritative record:CVE-2026-120459· Critical 9.1

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

CVSS 4.0 base score
9.1Critical
How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none
CVSS scores by source
CNA (VulnCheck)CVSS 4.09.1
CNA (VulnCheck)CVSS 3.17.4
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:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 2 Nov 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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

ProductAffectedFixed in
mpdavispython-joseAffected
  • <=3.5.0
Fixed in–
PyPIpython-josepkg:pypi/python-joseOther threatsAffected
  • <=3.5.0
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

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