# CVE-2026-27932: joserfc: joserfc is a Python library that provides an implementation of several JSON Object Signing and Encryption (JOSE) stan...

CVE-2026-27932 is fixed in 2 products on 1 platform, first by DEBIAN-CVE-2026-27932, released March 3, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-27932
- Priority: High
- CVSS: 7.5 (high)
- EPSS: 0.0046
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Mar 3, 2026

## Description

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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | joserfc Debian 14 | 1.6.3-1 | [DEBIAN-CVE-2026-27932](https://patchblox.com/security/data/fix/linux/debian-cve-2026-27932.md) | Mar 3, 2026 |
| Linux | python-joserfc opensuse-leap 16.0 | 1.1.0-bp160.2.1 | [OPENSUSE-SU-2026:20322-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-20322-1.md) | Mar 5, 2026 |

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Data as of 2026-11-08T19:12:23Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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