6.3
MEDIUM CVSS 4.0
CVE-2026-119602
libmspack through 0.11alpha Uninitialized Memory Disclosure via MS-ZIP Decompressor Window
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.

INFO

Published Date :

Oct. 30, 2026, 2:16 p.m.

Last Modified :

Oct. 30, 2026, 2:16 p.m.

Remotely Exploit :

Yes !
Affected Products

The following products are affected by CVE-2026-119602 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Libmspack_project libmspack
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 3.1 LOW 83251b91-4cc7-4094-a5c7-464a1b83ea10
CVSS 3.1 LOW MITRE-CVE
CVSS 3.1 LOW [email protected]
CVSS 4.0 MEDIUM 83251b91-4cc7-4094-a5c7-464a1b83ea10
CVSS 4.0 MEDIUM [email protected]
Solution
Update libmspack to patch uninitialized memory disclosure in MS-ZIP decompressor.
  • Update libmspack to a version after 0.11alpha.
  • Apply the vendor-provided patch for the MS-ZIP decompressor.
  • Validate decompression of crafted CAB files.
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-119602 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-119602 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-119602 vulnerability anywhere in the article.

The following table lists the changes that have been made to the CVE-2026-119602 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • New CVE Received by [email protected]

    Oct. 30, 2026

    Action Type Old Value New Value
    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.
    Added CVSS V4.0 AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
    Added CVSS V3.1 AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
    Added CWE CWE-908
    Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/119xxx/CVE-2026-119602.json">CVE-2026-119602</a>
    Added Reference https://github.com/kyz/libmspack
    Added Reference https://github.com/kyz/libmspack/blob/v0.11alpha/libmspack/mspack/mszipd.c#L264-L276
    Added Reference https://github.com/kyz/libmspack/issues/60
    Added Reference https://hackmd.io/@haindpwn/libmspack-mszip-uninit-window-info-leak
    Added Reference https://www.vulncheck.com/advisories/libmspack-through-0-11alpha-uninitialized-memory-disclosure-via-ms-zip-decompressor-window
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.