CVE-2026-102269 PyJWT: Non-canonical signature segments enable raw-token revocation bypass
Attackers can bypass raw-token revocation checks in PyJWT by using non-canonical Base64URL characters in the signature segment.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-102269?
CVE-2026-102269 is a medium-severity vulnerability in jpadilla pyjwt, published on 28 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
PyJWT is a Python implementation of JSON Web Token standards. Prior to 2.14.0, PyJWT signature segment is affected because signature segment decoding accepts characters outside the canonical Base64URL representation. This occurs when non-Base64URL characters are appended to a valid compact JWS signature segment. As a result, base64url_decode produces the same signature bytes for different serialized segments. Consequently, raw-token revocation checks can fail to recognize an equivalent modified token. This issue is fixed in version 2.14.0.
Weakness: CWE-180
Which versions are affected by CVE-2026-102269?
3 open source packages ship an affected version, including pyjwt and PyJWT. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
pyjwt PyPI | All versions | 2.14.0 |
pyjwt PyPI | All versions | 2.14.0 |
PyJWT PyPI | All versions | 2.14.0 |
Products include Pyjwt Project Pyjwt.
How do I fix CVE-2026-102269?
Upgrade pyjwt to 2.14.0 or later.
Is CVE-2026-102269 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-102269 exists.
Other vulnerabilities in jpadilla pyjwt
- CVE-2026-102268 PyJWT: Asymmetric-PEM detection bypass: whitespace/line-ending-mutated public keys skip the HS/asymmetric confusion guard
- CVE-2026-32597 PyJWT accepts unknown `crit` header extensions (RFC 7515 §4.1.11 MUST violation)
- CVE-2026-102266 PyJWK accepts empty HMAC keys, bypassing PyJWT's empty-key validation
- CVE-2026-102267 PyJWT: PyJWKClient follows redirects when fetching JWKS
- CVE-2026-102271 PyJWT: Public keys in DER form are accepted as HMAC secrets, bypassing the CVE-2022-29217 guard
Sources
Also known as AZL-104985, CLEANSTART-2026-CG08650, CLEANSTART-2026-DL13850, DEBIAN-CVE-2026-102269, ECHO-737a-6d67-3fbf, GHSA-hxm8-2xgr-2p9m and 27 more.