Vulnerability in Jpadilla Pyjwt

CVE-2026-48524

PyJWT is a JSON Web Token implementation in Python. Prior to 2.13.0, PyJWKClient.get_signing_key() forces a fresh HTTP request to the JWKS endpoint for every JWT with an unknown kid value, with no rate limiting. Since kid comes from the unverified token header, an attacker can trigger unlimited outbound requests. The vulnerability surfaces only when a JWKS fetch fails; an attacker can attempt to provoke that with sustained unknown-kid traffic, but the outcome depends on upstream JWKS-endpoint behavior (rate limiting, transient errors) which is beyond the attacker's control. This vulnerability is fixed in 2.13.0.

Published · last modified .

CVSS v3 metric

CVSS v3 base score 3.7 (Low). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L.

EPSS exploit prediction

EPSS: 0.003 (23.5th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 23rd percentile — 23.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-48524: held from 0.004 to 0.003.

EPSS over last 30 days · oldest: 0.004 · newest: 0.003 · change: -0.000

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-48524?
CVE-2026-48524 is a low-severity vulnerability in Jpadilla Pyjwt, classified under CWE-460. CVSS score: 3.7/10. Published 2026-05-28.
How severe is CVE-2026-48524?
Low severity. CVSS v3 base score is 3.7 out of 10.