CVE-2026-27932

The record

joserfc is a Python library that provides an implementation of several JSON Object Signing and Encryption (JOSE) standards. In 1.6.2 and earlier, a resource exhaustion vulnerability in joserfc allows an unauthenticated attacker to cause a Denial of Service (DoS) via CPU exhaustion. When the library decrypts a JSON Web Encryption (JWE) token using Password-Based Encryption (PBES2) algorithms, it reads the p2c (PBES2 Count) parameter directly from the token's protected header. This parameter defines the number of iterations for the PBKDF2 key derivation function. Because joserfc does not validate or bound this value, an attacker can specify an extremely large iteration count (e.g., 2^31 - 1), forcing the server to expend massive CPU resources processing a single token. This vulnerability exists at the JWA layer and impacts all high-level JWE and JWT decryption interfaces if PBES2 algorithms are allowed by the application's policy.

Affected packages

Related vulnerabilities

• GHSA-w5r5-m38g-f9f9 joserfc's PBES2 p2c Unbounded Iteration Count enables Denial of Service (DoS) Same vulnerability
• GHSA-frfh-8v73-gjg4 joserfc has Possible Uncontrolled Resource Consumption Vulnerability Triggered by Logging… Also affects joserfc
• CVE-2025-65015 joserfc has Possible Uncontrolled Resource Consumption Vulnerability Triggered by Logging… Also affects joserfc
• CVE-2026-48990 joserfc is a Python library that provides an implementation of several JSON Object… Also affects python-joserfc
• CVE-2026-114731 Roundcube Webmail before 1.6.20 and 1.7.x before 1.7.5 is affected by an uncontrolled… CWE-770
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• CVE-2026-96365 Allocation of Resources Without Limits or Throttling vulnerability in Drupal Webform… CWE-770
• CVE-2026-114723 Roundcube Webmail before 1.6.20 and 1.7.x before 1.7.5 allows the ImageMagick resource… CWE-770