# CVE-2026-104086: 7zip: 7-Zip before 26.03 contains an uninitialized memory disclosure vulnerability in the SquashFS v4 archive handler (Squa...

CVE-2026-104086 is fixed in 2 products on 1 platform, first by DEBIAN-CVE-2026-104086, released October 18, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-104086
- Priority: Routine
- CVSS: n/a
- EPSS: 0.0019
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Oct 14, 2026

## Description

7-Zip before 26.03 contains an uninitialized memory disclosure vulnerability in the SquashFS v4 archive handler (SquashfsHandler.cpp) that allows attackers to leak heap memory by crafting a malicious archive where the superblock’s no_ids field is set so that the final metadata block’s expected size is miscomputed and bypasses the size validation check. By listing or extracting the crafted archive, attackers can cause the application to return uninitialized heap memory as the kpidUserId and kpidGroupId properties, exposing potentially sensitive process memory contents to the user.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | 7zip Debian 14 | 26.03+dfsg-1 | [DEBIAN-CVE-2026-104086](https://patchblox.com/security/data/fix/linux/debian-cve-2026-104086.md) | Oct 18, 2026 |
| Linux | p7zip Debian 13.5 (trixie) | 16.02+transitional.1 | [DEBIAN-CVE-2026-104086](https://patchblox.com/security/data/fix/linux/debian-cve-2026-104086.md) | Oct 18, 2026 |

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Data as of 2026-11-09T13:31:49Z 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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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