CVE-2026-119602
libmspack through 0.11alpha Uninitialized Memory Disclosure via MS-ZIP Decompressor Window
- State
- Published
- Severity
- 6.3 Medium
- Published
- Oct 30, 2026
- Updated
- Oct 30, 2026
- Reserved
- Oct 30, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 6.3 Medium | 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 | VulnCheck |
| 3.1 | 3.7 Low | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N | VulnCheck |
Weaknesses
- CWE-908 Use of Uninitialized Resource
Affected Products
| Product | Versions |
|---|---|
libmspackkyz |
|
References
- https://github.com/kyz/libmspack/issues/60issue-tracking
- https://github.com/kyz/libmspack/blob/v0.11alpha/libmspack/mspack/mszipd.c#L264-L276technical-description
- https://hackmd.io/@haindpwn/libmspack-mszip-uninit-window-info-leakthird-party-advisory
- https://github.com/kyz/libmspackproduct
- VulnCheck Advisory: libmspack through 0.11alpha Uninitialized Memory Disclosure via MS-ZIP Decompressor Windowthird-party-advisory
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