CVE-2026-101917

pyjwt: PyJWT: Denial of Service via outbound request amplification on unknown key identifiers

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Severity

Moderate

Red Hat Product Security

5.3

CVSS 3.1

Review impact separately from score.

Published · September 29, 2026

Updated · October 30, 2026

Description

A flaw was found in PyJWT. A remote attacker can trigger a Denial of Service (DoS) through outbound request amplification by submitting tokens containing unknown key identifiers. Because the library does not cache lookup failures or enforce a minimum refresh interval when fetching signing keys, each invalid key identifier forces a new request to the remote JSON Web Key Set (JWKS) server. This allows an attacker to exhaust network resources and overwhelm the configured authentication endpoints.

CVSS score applicability

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation

No mitigation is specified in collected source.

CVSS / CWE

CVSS 3.1 · 5.3
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

CWE-408 · Incorrect Behavior Order: Early Amplification