vulnerability · Tue 29 Sep 2026 · 23:17 UTC
GHSA-ffc3-869f-jxw9: PyJWT: Asymmetric-PEM detection bypass: whitespace/line-ending-mutated public keys skip the HS/asymmetric
Filed UTCSource GTH ↗
Prerequisites (both conditions must hold; both are deployment properties, not attacker-controlled at request time): - The jwt.decode allow-list mixes an HMAC algorithm with an asymmetric one, e.g. algorithms=["ES256", "HS256"] (the RFC 8725 footgun the guard exists to backstop). - The verification key is passed as raw PEM text/bytes on the non-PyJWK path, in a byte-form that cryptography's loader accepts but PyJWT's is_pem_format regex does not recognize (marker-adjacent whitespace/indentation, CR-only line terminators, or the PEM folded to a single line). …
Signals
as the pipeline stamped them- High
- Critical vulnerability — CVSS 9.1
- What to do
- Critical severity — schedule an urgent patch.
CVE
KEV from CISA · EPSS from FIRST| Id | KEV | EPSS | Reference |
|---|---|---|---|
| CVE-2026-102268 | — | 0.20% | NVD ↗ |
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