GHSA-2gx3-rcp4-g85q: pyjwt (CVE-2026-101917)

Package	Ecosystem	Affected	Fixed in
pyjwt	PyPI	<2.14.0	2.14.0

Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

PyJWT versions before 2.14.0 cause PyJWKClient to send a fresh JWKS fetch for each unknown key ID (kid) in a token header, including repeated identical unknown values while the cache is valid. An unauthenticated attacker who can send tokens to the application can force repeated outbound requests and parsing work, which can exhaust resources or trigger rate limits at the identity provider. Upgrade to PyJWT 2.14.0, which adds a 30-second cooldown on unknown-kid refreshes.

Written 1 Nov 2026.

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

Score	Rating	CVSS	Vector	Source
5.3	Medium	3.1	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L	CNA (GitHub_M)

CISA KEV Not listed.
EPSS 0.0043, the 37th percentile, on 8 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

31 Oct 2026, 14:09 UTC First seen by agentprime
31 Oct 2026, 14:09 UTC Confirmed by OSV

Sources

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.