CVE-2023-0591 is a medium-severity (CVSS 5.5) Path Traversal vulnerability in ubi-reader. 1 public exploit reference exists, so weaponization risk is real. A fix is available for ubi-reader — see the affected versions and patch details below.
Path Traversal in ubi_reader
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
Exploitation and automatability from CISA’s SSVC triage for CVE-2023-0591.
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-2023-0591 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 377,333 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
ubi-readerReal-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
ubireader_extract_files is vulnerable to path traversal when run against specifically crafted UBIFS files, allowing the attacker to overwrite files outside of the extraction directory (provided the process has write access to that file or directory).
This is due to the fact that a node name (dent_node.name) is considered trusted and joined to the extraction directory path during processing, then the node content is written to that joined path. By crafting a malicious UBIFS file with node names holding path traversal payloads (e.g. ../../tmp/outside.txt), it's possible to force ubi_reader to write outside of the extraction directory.
This issue affects ubi-reader before 0.8.5.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | ubi-reader | all versions | 0.8.5pip install --upgrade 'ubi-reader==0.8.5' |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for ubi-reader, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update ubi-reader to 0.8.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-0591 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-2023-0591 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2023-0591. 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-2023-0591 in your dependencies?
O3 Security finds CVE-2023-0591 across PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.