Uncontrolled Recursion in pyjwt - CVE-2026-102265
Published: September 17, 2026 / Updated: September 29, 2026
Vulnerability identifier: #VU150521
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-2026-102265
CWE-ID: CWE-674
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to uncontrolled recursion in the PyJWS._load() header JSON parsing path when processing a compact token with a deeply nested JSON header. A remote attacker can send an unsigned crafted token to cause a denial of service.
The header is parsed before signature verification, and the resulting exception can bypass applications' normal PyJWT error handling.
Affected software
pyjwt
openEuler
python-jwt
python-jwt-help
python3-jwt
openEuler
python-jwt
python-jwt-help
python3-jwt
How to mitigate CVE-2026-102265
Install security update from vendor's website.
pyjwt - update to 2.14.0
python-jwt - addressed in versions 2.3.0-12, 2.8.0-11
python-jwt-help - addressed in versions 2.3.0-12, 2.8.0-11
python3-jwt - addressed in versions 2.3.0-12, 2.8.0-11
python-jwt - addressed in versions 2.3.0-12, 2.8.0-11
python-jwt-help - addressed in versions 2.3.0-12, 2.8.0-11
python3-jwt - addressed in versions 2.3.0-12, 2.8.0-11