Resource Exhaustion Affecting pyjwt package, versions <2.10.1-4ubuntu1.1


Severity

Recommended
medium

Based on Ubuntu security rating.

Threat Intelligence

EPSS
0.42% (34th percentile)

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  • Snyk IDSNYK-UBUNTU2604-PYJWT-17092505
  • published16 Sept 2026
  • disclosed28 May 2026

Introduced: 28 May 2026

CVE-2026-48525  (opens in a new tab)
CWE-400  (opens in a new tab)

How to fix?

Upgrade Ubuntu:26.04 pyjwt to version 2.10.1-4ubuntu1.1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream pyjwt package and not the pyjwt package as distributed by Ubuntu. See How to fix? for Ubuntu:26.04 relevant fixed versions and status.

PyJWT is a JSON Web Token implementation in Python. From 2.8.0 to 2.12.1, when verifying detached JWS tokens using the unencoded-payload option ("b64": false, RFC 7797), PyJWT performs Base64URL decoding of the compact-serialization payload segment before enforcing the detached-payload rules. For b64=false, PyJWT later discards that decoded payload and replaces it with the caller-provided detached_payload. In practice, this turns the middle segment into an attacker-controlled “work amplifier”: a remote client can supply an arbitrarily large Base64URL payload segment that forces CPU work + memory allocations even if the signature is invalid. This creates an unauthenticated DoS vector against any endpoint that verifies detached JWS using PyJWT. This vulnerability is fixed in 2.13.0.

CVSS Base Scores

version 3.1