# CVE-2026-110602: libmspack through 0.11alpha Uninitialized Pointer Free via kwajd_open Error Path

CVE-2026-110602 is fixed in 3 products on 1 platform, first by DEBIAN-CVE-2026-110602, released October 27, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-110602
- Priority: Routine
- CVSS: 6.3 (Moderate)
- EPSS: 0.0024
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Oct 14, 2026
- Weakness: Access of Uninitialized Pointer
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-110602

## Description

libmspack through 0.11alpha contains an uninitialized pointer free vulnerability in kwajd_open() in mspack/kwajd.c that frees unzeroed filename and extra pointers on header read errors. Attackers can supply a truncated, empty, or wrong-signature KWAJ file to crash the process or obtain an arbitrary-free memory corruption primitive.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | libmspack Debian 14 | 0.11-2 | [DEBIAN-CVE-2026-110602](https://patchblox.com/security/data/fix/linux/debian-cve-2026-110602.md) | Oct 27, 2026 |
| Linux | libmspack0 Ubuntu 22.04.1 LTS (jammy) | 0.10.1-2ubuntu0.1 | [libmspack0 0.10.1-2ubuntu0.1](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-libmspack0-0.10.1-2ubuntu0.1.md) | Nov 4, 2026 |
| Linux | libmspack0t64 Ubuntu 24.04.5 LTS (noble) | 0.11-1.1ubuntu0.24.04.1 | [libmspack0t64 0.11-1.1ubuntu0.24.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libmspack0t64-0.11-1.1ubuntu0.24.04.1.md) | Nov 4, 2026 |
| Linux | libmspack0t64 Ubuntu 26.04.1 LTS (resolute) | 0.11-1.1ubuntu0.26.04.1 | [libmspack0t64 0.11-1.1ubuntu0.26.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-libmspack0t64-0.11-1.1ubuntu0.26.04.1.md) | Nov 7, 2026 |

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Data as of 2026-11-08T13:06:02Z 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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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