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Ubuntu Security NoticesUSN-8823-1

USN-8823-1: PyJWT vulnerabilities

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)

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Scope

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  1. Published by Ubuntu

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  2. Added to SecurityAlert

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Vulnerabilities

CVEs named in this advisory