QSN-8823-1: PyJWT vulnerabilities
2026-09-25

Summary:
Several security issues were fixed in PyJWT.

Details:
It was discovered that PyJWT incorrectly handled certain URIs when using
PyJWKClient. A remote attacker could possibly use this issue to perform
server-side request forgery (SSRF) or expose sensitive local files.
This issue only affected Ubuntu 22.04 LTS, Ubuntu 24.04 LTS and Ubuntu
26.04 LTS. (CVE-2026-48522)

It was discovered that PyJWT incorrectly verified cryptographic signatures
when decoding tokens with PyJWK keys. A remote attacker could possibly
use this issue to bypass signature verification and forge valid JSON Web
Tokens. This issue only affected Ubuntu 26.04 LTS. (CVE-2026-48523)

It was discovered that PyJWT incorrectly handled unknown key identifiers
in PyJWKClient. A remote attacker could possibly use this issue to cause
PyJWT to make excessive network requests, resulting in a denial of service.
This issue only affected Ubuntu 24.04 LTS and Ubuntu 26.04 LTS.
(CVE-2026-48524)

It was discovered that PyJWT incorrectly handled payload decoding during
detached JWS token verification. A remote attacker could possibly use
this issue to cause PyJWT to consume excessive resources, resulting in
a denial of service. This issue only affected Ubuntu 24.04 LTS and
Ubuntu 26.04 LTS. (CVE-2026-48525)

It was discovered that PyJWT incorrectly validated JSON Web Keys when
decoding tokens with both HMAC and asymmetric algorithms enabled. A remote
attacker could possibly use this issue to forge valid tokens, resulting
in an authentication bypass. (CVE-2026-48526)

Affected QuantaStor releases:
  6.9.1.001 jammy: python3-jwt 2.3.0-1ubuntu0.6 (fixed in 2.3.0-1ubuntu0.4)
  6.9.0.464 jammy: python3-jwt 2.3.0-1ubuntu0.5 (fixed in 2.3.0-1ubuntu0.4)
  6.8.6.015 jammy: python3-jwt 2.3.0-1ubuntu0.3 (fixed in 2.3.0-1ubuntu0.4)
  6.8.5.018 jammy: python3-jwt 2.3.0-1ubuntu0.3 (fixed in 2.3.0-1ubuntu0.4)
  6.8.4.038 jammy: python3-jwt 2.3.0-1ubuntu0.3 (fixed in 2.3.0-1ubuntu0.4)
  6.8.3.018 jammy: python3-jwt 2.3.0-1ubuntu0.3 (fixed in 2.3.0-1ubuntu0.4)
  6.8.2.002 jammy: python3-jwt 2.3.0-1ubuntu0.3 (fixed in 2.3.0-1ubuntu0.4)
  6.8.1.007 jammy: python3-jwt 2.3.0-1ubuntu0.3 (fixed in 2.3.0-1ubuntu0.4)
  6.8.0.205 jammy: python3-jwt 2.3.0-1ubuntu0.3 (fixed in 2.3.0-1ubuntu0.4)

CVEs: CVE-2026-48524, CVE-2026-48526, CVE-2026-48525, CVE-2026-48523, CVE-2026-48522

References:
  https://ubuntu.com/security/notices/USN-8823-1