libmspack through 0.11alpha contains an uninitialized memory disclosure vulnerability in the MS-ZIP decompressor that allows attackers to leak heap data via unchecked back-reference distances. Attackers can supply a crafted MS-ZIP CAB file whose first block begins with a back-reference, causing cabd->extract() to write up to 32 KiB of stale heap memory into extracted output.

Attack Vector Network

Attack Complexity Low

Privileges Required None

Attack Requirements Present

User Interaction None

Vulnerable System Confidentiality Impact Low

Vulnerable System Integrity Impact None

Vulnerable System Availability Impact None

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity High

Privileges Required None

Scope Unchanged

Confidentiality Impact Low

Integrity Impact None

Availability Impact None

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
kyz libmspack unaffected
Version Status Constraints
0 affected ≤ 0.11alpha

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Project Subscriptions

Vendors Products
Libmspack Project Subscribe
Libmspack Subscribe
Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/kyz/libmspack cve-icon cve-icon
https://github.com/kyz/libmspack/blob/v0.11alpha/libmspack/mspack/mszipd.c#L264-L276 cve-icon cve-icon
https://github.com/kyz/libmspack/issues/60 cve-icon cve-icon
https://hackmd.io/@haindpwn/libmspack-mszip-uninit-window-info-leak cve-icon cve-icon
https://www.vulncheck.com/advisories/libmspack-through-0-11alpha-uninitialized-memory-disclosure-via-ms-zip-decompressor-window cve-icon cve-icon
History

Fri, 30 Oct 2026 13:30:00 +0000

Type Values Removed Values Added
Description libmspack through 0.11alpha contains an uninitialized memory disclosure vulnerability in the MS-ZIP decompressor that allows attackers to leak heap data via unchecked back-reference distances. Attackers can supply a crafted MS-ZIP CAB file whose first block begins with a back-reference, causing cabd->extract() to write up to 32 KiB of stale heap memory into extracted output.
Title libmspack through 0.11alpha Uninitialized Memory Disclosure via MS-ZIP Decompressor Window
First Time appeared Libmspack Project
Libmspack Project libmspack
Weaknesses CWE-908
CPEs cpe:2.3:a:libmspack_project:libmspack:*:*:*:*:*:*:*:*
Vendors & Products Libmspack Project
Libmspack Project libmspack
References
Metrics cvssV3_1

{'score': 3.7, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N'}

cvssV4_0

{'score': 6.3, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-10-30T15:53:29.159Z

Reserved: 2026-10-30T11:46:47.302Z

Link: CVE-2026-119602

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Deferred

Published: 2026-10-30T14:16:48.700

Modified: 2026-10-30T14:16:48.850

Link: CVE-2026-119602

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-10-30T14:45:14Z

Weaknesses