How severe is CVE-2026-54559?

No CVSS score has been assigned to CVE-2026-54559 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-54559?

CVE-2026-54559 affects the following packages: pocketsphinx (PyPI). Ecosystems affected: PyPI.

How do I fix CVE-2026-54559?

Update pocketsphinx to 5.1.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-54559 is resolved across your whole dependency graph.

How do I detect CVE-2026-54559 in my PyPI dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for pocketsphinx, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-54559 if there is no patch (or I can't update yet)?

Constrain what reaches the vulnerable code: limit the size and shape of untrusted input, isolate the affected component in a sandboxed or least-privileged process, and enable the platform's memory-safety mitigations (ASLR, stack protector, hardened allocator) so an out-of-bounds access is more likely to fail closed than to be exploitable.

Is CVE-2026-54559 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-54559 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-54559?

CVE-2026-54559 has an EPSS (Exploit Prediction Scoring System) score of 0.5%, placing it in the 45th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-54559?

CVE-2026-54559 is classified as Buffer Overflow (CWE-119), CWE-121 (CWE-121), CWE-122 (CWE-122). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2026-54559 published, and has it been updated?

CVE-2026-54559 was published on September 14, 2026 and was last updated on October 21, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐍 PyPI

Not in CISA KEV

CVE-2026-54559 — pocketsphinx

Fix: cmusphinx/pocketsphinx@2a3c037

CVE-2026-54559 is a Buffer Overflow vulnerability in pocketsphinx. A fix is available for pocketsphinx — see the affected versions and patch details below.

PocketSphinx: Buffer overflows in language and acoustic model loading code

Also known asGHSA-56r5-2p2f-7cxpPYSEC-2026-3498

Published

Sep 14, 2026

Updated

Oct 21, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Oct 23, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-54559.

EPSS Exploitation Probability

via FIRST.org ↗

0.5%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs45th percentile — riskier than 45% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

1 pkg affected

🐍pocketsphinx

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

Impact

The trie language model code introduced in PocketSphinx 5prealpha failed to check various boundary conditions when reading the headers of ARPA, DMP, and binary format language model files. In the case of invalid, corrupted or malicious input files, this could lead to stack and heap buffer overflows.

In addition, the acoustic model loading code (which is over 30 years old...) contains numerous instances of sscanf with an unbounded string field which could also lead to stack overflows in the case of corrupt or malicious inputs.

Because PocketSphinx will search the directory given by the POCKETSPHINX_PATH environment variable for acoustic and language model files, if this directory is writable by untrusted users, an attacker could corrupt an existing file or write a malicious one to this directory in order to trigger the vulnerability.

Patches

The problem has been corrected in PocketSphinx 5.1.1.

There is no patch currently available for users of Pocketsphinx 5prealpha, who are encouraged to migrate as soon as possible to PocketSphinx 5.1.1.

Workarounds

Ensure that the POCKETSPHINX_PATH environment variable is either unset, or set to a directory whose contents are trusted and which cannot be written by untrusted users.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐍PyPI	`pocketsphinx`	all versions	5.1.1`pip install --upgrade 'pocketsphinx==5.1.1'`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for pocketsphinx, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update pocketsphinx to 5.1.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-54559 is resolved across your whole dependency graph.
Workarounds
Constrain what reaches the vulnerable code: limit the size and shape of untrusted input, isolate the affected component in a sandboxed or least-privileged process, and enable the platform's memory-safety mitigations (ASLR, stack protector, hardened allocator) so an out-of-bounds access is more likely to fail closed than to be exploitable.

Frequently Asked Questions

### Impact The trie language model code introduced in PocketSphinx 5prealpha failed to check various boundary conditions when reading the headers of ARPA, DMP, and binary format language model files. In the case of invalid, corrupted or malicious input files, this could lead to stack and heap buffer overflows. In addition, the acoustic model loading code (which is over 30 years old...) contains numerous instances of `sscanf` with an unbounded string field which could also lead to stack overflows in the case of corrupt or malicious inputs. Because PocketSphinx will search the directory give

O3 Security · Impact-Aware SCA

Is CVE-2026-54559 in your dependencies?

Find it across PyPI, including transitive dependencies.

Scan my dependencies How O3 SCA works