CVE-2026-102267: PyJWT: PyJWKClient follows redirects when fetching JWKS
PyJWT is a Python implementation of JSON Web Token standards. Prior to 2.14.0, PyJWT PyJWKClient is affected because redirect destinations are not revalidated against the JWKS trust boundary. This occurs when a configured trusted JWKS endpoint returns an attacker-influenced redirect. As a result, PyJWKClient follows the redirect and consumes the redirected response as key material. Consequently, forwarded credentials may be disclosed or verification keys may be substituted. This issue is fixed in version 2.14.0.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
PyJWTto a version that resolves this vulnerability.Fixed in 2.14.0
Event History
Frequently Asked Questions
Which deployments are exposed to this issue?
Deployments using PyJWT PyJWKClient before version 2.14.0 are affected when they fetch keys from a configured trusted JWKS endpoint that can return an attacker-influenced redirect.
What does an attacker need to exploit it?
An attacker needs influence over a redirect returned by the configured JWKS endpoint. PyJWKClient then follows the redirect without revalidating the destination against the JWKS trust boundary.
What is the impact of a successful exploit?
Forwarded credentials may be disclosed to the redirect destination, or the redirected response may be consumed as key material, allowing verification keys to be substituted.
What is the available remediation?
Upgrade PyJWT to version 2.14.0, which fixes the redirect handling issue.