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VulnerabilityPublished

CVE-2026-102269: jpadilla pyjwt · Incorrect Behavior Order: Validate Before Canonicalize

Affects jpadilla pyjwtSource CVE Database V5

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Not known to be exploited · CVSS 4.8 Medium : upgrade to 2.14.0 when convenient.

Data as of 12 Nov 2026, 23:24 UTC

CVSS 3.1 base score
4.8Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.2% chance of exploitation in 30 days – higher than 13% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 2.14.0
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 28 Sep 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 13 Nov 2026.

What to do

Upgrade jpadilla pyjwt to 2.14.0.

Affected software

ProductAffectedFixed in
jpadillapyjwtAffected
  • <2.14.0
Fixed in
  • 2.14.0
PyPIpyjwtpkg:pypi/pyjwtOther threatsAffected
  • <2.14.0
Fixed in
  • 2.14.0

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A fix rejecting non-canonical Base64URL characters in signature segments is prepared but not yet released. If you cannot patch yet, applications should avoid relying solely on the raw serialized token string for security decisions such as logout or revocation.

Description

PyJWT versions prior to 2.14.0 accept JWS signature segments with non-canonical Base64URL characters, which do not affect the decoded signature or claims but alter the serialized token and its hash. This can allow bypass of logout or revocation mechanisms that rely on the raw serialized token as a security identity. The issue is not related to signature forgery and requires possession of a valid token. A fix rejecting such non-canonical characters is prepared but not yet released.

References

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