transmute-core unsafe YAML deserialization vulnerabilityGHSA-w9cp-3x79-2p8p
CRITICALFix: toumorokoshi/transmute-core#58GHSA-w9cp-3x79-2p8p is a critical-severity (CVSS 9.8) Deserialization of Untrusted Data vulnerability in transmute-core. A fix is available for transmute-core — see the affected versions and patch details below.
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.
- A successful exploit gives an attacker total control of the affected component, not partial access.
- 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 GHSA-w9cp-3x79-2p8p.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
transmute-coreReal-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
Unsafe YAML deserialization in yaml.Loader in transmute-core before 1.13.5 allows attackers to execute arbitrary Python code.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | transmute-core | all versions | 1.13.5pip install --upgrade 'transmute-core==1.13.5' |
Affected Products
transmute-coretoumorokoshiDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for transmute-core, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update transmute-core to 1.13.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-w9cp-3x79-2p8p is resolved across your whole dependency graph.
Workarounds
Do not deserialise data from untrusted sources: where the format allows it, restrict deserialisation to an explicit allowlist of expected types, and prefer a data-only format (JSON, Protobuf) over one that can reconstruct arbitrary objects until you can upgrade.
Frequently Asked Questions
Is GHSA-w9cp-3x79-2p8p in your dependencies?
Find it across PyPI, including transitive dependencies.