Allocation of Resources Without Limits or Throttling in pyjwt - CVE-2026-101917

Vulnerability identifier: #VU158761

CSH Severity: Medium

CVSS v4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-101917

CWE-ID: CWE-770

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to cause a denial of service through excessive outbound JWKS requests and repeated parsing work.

The vulnerability exists due to resource allocation without throttling in PyJWT's PyJWKClient when processing unverified token headers containing unknown key identifiers. A remote attacker can submit tokens with unknown kid values to force repeated JWKS fetches, bypassing an otherwise valid cache and consuming server resources to cause a denial of service.

pyjwt
SUSE Linux Enterprise Server 15 SP6
SUSE Linux Enterprise Server 15 SP5
SUSE Linux Enterprise Server 15 SP4
SUSE Linux Enterprise Server 15
SUSE Linux Enterprise High Performance Computing 15
SUSE Linux Enterprise High Performance Computing ESPOS 15
SUSE Linux Enterprise High Performance Computing LTSS 15
SUSE Linux Enterprise Server for SAP Applications 15
SUSE Linux Enterprise Desktop 15
SUSE Manager Server
SUSE Manager Proxy
SUSE Manager Retail Branch Server
Public Cloud Module
Python 3 Module
openSUSE Leap
Ubuntu
openEuler
python3-jwt (Ubuntu package)
python-jwt (Ubuntu package)
python-jwt-help
python3-jwt
python-jwt
python311-PyJWT

Install security update from vendor's website.

pyjwt - update to 2.14.0
python3-jwt (Ubuntu package) - addressed in versions 1.3.0-1ubuntu0.1+esm4, 1.5.3+ds1-1ubuntu0.1+esm4, 1.7.1-2ubuntu2.1+esm4, 2.3.0-1ubuntu0.6, 2.7.0-1ubuntu0.4, 2.10.1-4ubuntu1.3, 2.13.0-1ubuntu1.1
python-jwt (Ubuntu package) - addressed in versions 1.3.0-1ubuntu0.1+esm4, 1.5.3+ds1-1ubuntu0.1+esm4
python-jwt-help - update to 2.8.0-11
python3-jwt - update to 2.8.0-11
python-jwt - update to 2.8.0-11
python311-PyJWT - update to 2.8.0-150400.8.20.1

• https://github.com/jpadilla/pyjwt/security/advisories/GHSA-2gx3-rcp4-g85q
• https://github.com/jpadilla/pyjwt/commit/ba4853a

• Multiple vulnerabilities in pyjwt
• openEuler 24.03 LTS SP3 update for python-jwt
• openEuler 24.03 LTS SP1 update for python-jwt
• openEuler 24.03 LTS SP4 update for python-jwt
• Ubuntu update for pyjwt
• SUSE update for python-PyJWT