QSN-8934-1: PyJWT vulnerabilities
2026-10-19

Summary:
Several security issues were fixed in PyJWT.

Details:
Kingsley Olukanni discovered that PyJWT did not properly handle unknown key
identifiers when retrieving signing keys. An attacker could possibly use
this issue to amplify requests to the configured key endpoint, resulting in
a denial of service. This issue only affected Ubuntu 22.04 LTS, Ubuntu
24.04 LTS, Ubuntu 26.04 LTS and Ubuntu 26.10. (CVE-2026-101917)

Ekalabya Ghosh discovered that PyJWT did not properly handle certain
recursively nested JSON payloads. An attacker could possibly use this issue
to cause an application to fail, resulting in a denial of service.
(CVE-2026-101918)

Pedram Hayati discovered that PyJWT did not properly handle malformed RSA
keys in a JSON Web Key Set. An attacker could possibly use this issue to
cause authentication failures or a denial of service. This issue only
affected Ubuntu 22.04 LTS, Ubuntu 24.04 LTS,  Ubuntu 26.04 LTS and Ubuntu
26.10. (CVE-2026-102274)

It was discovered that PyJWT did not properly validate certain OKP private
key components. An attacker could possibly use this issue to confuse the
identity of public and private keys, and use a stolen sender-constrained
token without the legitimate private key. This issue only affected Ubuntu
22.04 LTS, Ubuntu 24.04 LTS, Ubuntu 26.04 LTS and Ubuntu 26.10.
(CVE-2026-102275)

Affected QuantaStor releases:
  6.9.1.001 jammy: python3-jwt 2.3.0-1ubuntu0.6 (fixed in 2.3.0-1ubuntu0.6)
  6.9.0.464 jammy: python3-jwt 2.3.0-1ubuntu0.5 (fixed in 2.3.0-1ubuntu0.6)
  6.8.6.015 jammy: python3-jwt 2.3.0-1ubuntu0.3 (fixed in 2.3.0-1ubuntu0.6)
  6.8.5.018 jammy: python3-jwt 2.3.0-1ubuntu0.3 (fixed in 2.3.0-1ubuntu0.6)
  6.8.4.038 jammy: python3-jwt 2.3.0-1ubuntu0.3 (fixed in 2.3.0-1ubuntu0.6)
  6.8.3.018 jammy: python3-jwt 2.3.0-1ubuntu0.3 (fixed in 2.3.0-1ubuntu0.6)
  6.8.2.002 jammy: python3-jwt 2.3.0-1ubuntu0.3 (fixed in 2.3.0-1ubuntu0.6)
  6.8.1.007 jammy: python3-jwt 2.3.0-1ubuntu0.3 (fixed in 2.3.0-1ubuntu0.6)
  6.8.0.205 jammy: python3-jwt 2.3.0-1ubuntu0.3 (fixed in 2.3.0-1ubuntu0.6)

CVEs: CVE-2026-101918, CVE-2026-102275, CVE-2026-102274, CVE-2026-101917

References:
  https://ubuntu.com/security/notices/USN-8934-1