CVE-2026-42351 is a high-severity (CVSS 7.5) Path Traversal vulnerability in pygeoapi. A fix is available for pygeoapi — see the affected versions and patch details below.
pygeoapi: Path Traversal in STAC FileSystemProvider
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-2026-42351.
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-2026-42351 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 377,636 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
pygeoapiReal-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
A raw string path concatenation vulnerability in pygeoapi's STAC FileSystemProvider plugin can allow for requests to STAC collection based collections to expose directories without authentication. The issue manifests when pygeoapi is deployed without a proxy or web front end that would normalize URLs with .. values, along with a resource of type stac-collection defined in configuration.
Patches
The issue has been patched in master branch and made available as part of the 0.23.3 release.
The commit/fix can be found in bf25b8695edbdd5476eeffc102b633d1d3e45f52.
Workarounds
Users can safeguard existing applications by disabling STAC collection based resources in their pygeoapi config, until 0.23.3 can be installed and deployed.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | pygeoapi | ≥ 0.23.0&&< 0.23.3 | 0.23.3pip install --upgrade 'pygeoapi==0.23.3' |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for pygeoapi, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update pygeoapi to 0.23.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-42351 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-2026-42351 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-42351. 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-2026-42351 in your dependencies?
O3 Security finds CVE-2026-42351 across PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.