CVE-2026-45727
CVE-2026-45727 is a Path Traversal vulnerability in cloakbrowser. O3 Security confirms whether CVE-2026-45727 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
CloakBrowser: Unauthenticated path traversal via fingerprint parameter in cloakserve leads to arbitrary directory deletion
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-2026-45727.
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.
Real-World Exposure
cloakbrowserReal-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
CloakBrowser is a tool to bypass bot detection tests. Prior to version 0.3.28, the cloakserve CDP multiplexer uses the user-supplied fingerprint query parameter directly as a filesystem path component when creating Chrome profile directories. An unauthenticated attacker who can reach the cloakserve port can supply a crafted fingerprint value containing path traversal sequences to resolve user_data_dir outside the configured data_dir. When Chrome fails to start or the process is cleaned up, shutil.rmtree() deletes the traversed path, resulting in arbitrary directory deletion. Additionally, cloakserve bound to 0.0.0.0 by default, making it network-exposed. This issue has been patched in version 0.3.28.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | cloakbrowser | all versions | 0.3.28 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for cloakbrowser. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update cloakbrowser to 0.3.28 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-45727 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 pinpoints whether CVE-2026-45727 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-45727. 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-2026-45727 in your dependencies?
O3 detects CVE-2026-45727 across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.