# CVE-2026-18938: p11-kit: A flaw was found in p11-kit

CVE-2026-18938 is fixed in 3 products on 1 platform, first by DEBIAN-CVE-2026-18938, released August 22, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-18938
- Priority: Routine
- CVSS: 6.2 (medium)
- EPSS: 0.0011
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Aug 7, 2026

## Description

A flaw was found in p11-kit. A local attacker, or one with equivalent access to a reachable RPC channel, could exploit an integer overflow vulnerability. By sending specially crafted messages, the attacker can cause the system to miscalculate memory allocation for nested attributes. This leads to a memory corruption issue, specifically a heap out-of-bounds write, which can crash the p11-kit RPC parsing process, resulting in a Denial of Service (DoS). This vulnerability is only exploitable on 32 bit systems.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | libp11-kit0 Ubuntu 18.04.6 LTS (bionic) | 0.23.9-2ubuntu0.1+esm1 | [libp11-kit0 0.23.9-2ubuntu0.1+esm1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libp11-kit0-0.23.9-2ubuntu0.1-esm1.md) | Sep 3, 2026 |
| Linux | libp11-kit0 Ubuntu 20.04 LTS (focal) | 0.23.20-1ubuntu0.1+esm1 | [libp11-kit0 0.23.20-1ubuntu0.1+esm1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libp11-kit0-0.23.20-1ubuntu0.1-esm1.md) | Sep 3, 2026 |
| Linux | libp11-kit0 Ubuntu 22.04.1 LTS (jammy) | 0.24.0-6ubuntu0.1 | [libp11-kit0 0.24.0-6ubuntu0.1](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-libp11-kit0-0.24.0-6ubuntu0.1.md) | Sep 3, 2026 |
| Linux | libp11-kit0 Ubuntu 24.04.5 LTS (noble) | 0.25.3-4ubuntu2.2 | [libp11-kit0 0.25.3-4ubuntu2.2](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libp11-kit0-0.25.3-4ubuntu2.2.md) | Sep 3, 2026 |
| Linux | p11-kit Debian 14 | 0.26.5-1 | [DEBIAN-CVE-2026-18938](https://patchblox.com/security/data/fix/linux/debian-cve-2026-18938.md) | Aug 22, 2026 |
| Linux | p11-kit Ubuntu 18.04.6 LTS (bionic) | 0.23.9-2ubuntu0.1+esm1 | [p11-kit 0.23.9-2ubuntu0.1+esm1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-p11-kit-0.23.9-2ubuntu0.1-esm1.md) | Sep 3, 2026 |
| Linux | p11-kit Ubuntu 20.04 LTS (focal) | 0.23.20-1ubuntu0.1+esm1 | [p11-kit 0.23.20-1ubuntu0.1+esm1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-p11-kit-0.23.20-1ubuntu0.1-esm1.md) | Sep 3, 2026 |
| Linux | p11-kit Ubuntu 22.04.1 LTS (jammy) | 0.24.0-6ubuntu0.1 | [p11-kit 0.24.0-6ubuntu0.1](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-p11-kit-0.24.0-6ubuntu0.1.md) | Sep 3, 2026 |
| Linux | p11-kit Ubuntu 24.04.5 LTS (noble) | 0.25.3-4ubuntu2.2 | [p11-kit 0.25.3-4ubuntu2.2](https://patchblox.com/security/data/fix/linux/ubuntu-noble-p11-kit-0.25.3-4ubuntu2.2.md) | Sep 3, 2026 |
| Linux | p11-kit opensuse-leap 16.0 | 0.25.5-160000.3.1 | [OPENSUSE-SU-2026:22105-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22105-1.md) | Nov 7, 2026 |
| Linux | p11-kit sles 16.0 | 0.25.5-160000.3.1 | [SUSE-SU-2026:24255-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-24255-1.md) | Nov 7, 2026 |
| Linux | p11-kit-modules Ubuntu 18.04.6 LTS (bionic) | 0.23.9-2ubuntu0.1+esm1 | [p11-kit-modules 0.23.9-2ubuntu0.1+esm1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-p11-kit-modules-0.23.9-2ubuntu0.1-esm1.md) | Sep 3, 2026 |
| Linux | p11-kit-modules Ubuntu 20.04 LTS (focal) | 0.23.20-1ubuntu0.1+esm1 | [p11-kit-modules 0.23.20-1ubuntu0.1+esm1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-p11-kit-modules-0.23.20-1ubuntu0.1-esm1.md) | Sep 3, 2026 |
| Linux | p11-kit-modules Ubuntu 22.04.1 LTS (jammy) | 0.24.0-6ubuntu0.1 | [p11-kit-modules 0.24.0-6ubuntu0.1](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-p11-kit-modules-0.24.0-6ubuntu0.1.md) | Sep 3, 2026 |
| Linux | p11-kit-modules Ubuntu 24.04.5 LTS (noble) | 0.25.3-4ubuntu2.2 | [p11-kit-modules 0.25.3-4ubuntu2.2](https://patchblox.com/security/data/fix/linux/ubuntu-noble-p11-kit-modules-0.25.3-4ubuntu2.2.md) | Sep 3, 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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