CVE-2025-55013 — assemblyline-service-clie…
MEDIUMFix: CybercentreCanada/assemblyline-service-client@351414eCVE-2025-55013 is a medium-severity (CVSS 4.2) CWE-23 vulnerability in assemblyline-service-client. A fix is available for assemblyline-service-client — see the affected versions and patch details below.
Assemblyline 4 Service Client: Arbitrary Write through path traversal in Client code
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-2025-55013.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2025-55013 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 376,715 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
assemblyline-service-client🐍assemblyline-service-clientReal-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
The Assemblyline 4 Service Client interfaces with the API to fetch tasks and publish the result for a service in Assemblyline 4. In versions below 4.6.1.dev138, the Assemblyline 4 Service Client (task_handler.py) accepts a SHA-256 value returned by the service server and uses it directly as a local file name.A malicious or compromised server (or any MITM that can speak to client) can return a path-traversal payload such as ../../../etc/cron.d/evil and force the client to write the downloaded bytes to an arbitrary location on disk. This is fixed in version 4.6.1.dev138.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | assemblyline-service-client | all versions | 4.6.0.stable11pip install --upgrade 'assemblyline-service-client==4.6.0.stable11' |
| 🐍PyPI | assemblyline-service-client | ≥ 4.6.1.dev0&&< 4.6.1.dev138 | 4.6.1.dev138pip install --upgrade 'assemblyline-service-client==4.6.1.dev138' |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for assemblyline-service-client, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update assemblyline-service-client to 4.6.0.stable11 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-55013 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2025-55013 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2025-55013. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2025-55013 in your dependencies?
O3 Security finds CVE-2025-55013 across PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.