How severe is GHSA-4hpq-rjcx-7vj9?

GHSA-4hpq-rjcx-7vj9 has a CVSS score of 7.6/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by GHSA-4hpq-rjcx-7vj9?

GHSA-4hpq-rjcx-7vj9 affects the following packages: clearance (RubyGems). Ecosystems affected: RubyGems.

How do I fix GHSA-4hpq-rjcx-7vj9?

Update clearance to 2.5.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-4hpq-rjcx-7vj9 is resolved across your whole dependency graph.

How do I detect GHSA-4hpq-rjcx-7vj9 in my RubyGems dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for clearance. 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.

How do I mitigate GHSA-4hpq-rjcx-7vj9 if there is no patch (or I can't update yet)?

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 does O3 Security protect against GHSA-4hpq-rjcx-7vj9?

O3 pinpoints whether GHSA-4hpq-rjcx-7vj9 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is GHSA-4hpq-rjcx-7vj9 actively exploited in the wild?

No public exploit code has been indexed for GHSA-4hpq-rjcx-7vj9 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for GHSA-4hpq-rjcx-7vj9?

GHSA-4hpq-rjcx-7vj9 has an EPSS (Exploit Prediction Scoring System) score of 0.7%, placing it in the 47th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

When was GHSA-4hpq-rjcx-7vj9 published, and has it been updated?

GHSA-4hpq-rjcx-7vj9 was published on September 13, 2021 and was last updated on March 13, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

💎 RubyGems

GHSA-4hpq-rjcx-7vj9

HIGH

Clearance Gem Open Redirect Vulnerability

Also known asCVE-2021-23435

Published

Sep 13, 2021

Updated

Mar 13, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

EPSS Exploitation Probability

via FIRST.org ↗

0.7%probability of exploitation in next 30 days

Lower Risk47th percentile+0.39%

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.

Blast Radius

1 pkg affected

💎clearance

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects RubyGems packages — download data is not available via public APIs for these ecosystems.

Description

This affects the package clearance before 2.5.0. The vulnerability can be possible when users are able to set the value of session[:return_to]. If the value used for return_to contains multiple leading slashes (/////example.com) the user ends up being redirected to the external domain that comes after the slashes (http://example.com).

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
💎RubyGems	`clearance`	all versions	2.5.0

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for clearance. 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 clearance to 2.5.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-4hpq-rjcx-7vj9 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 GHSA-4hpq-rjcx-7vj9 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 GHSA-4hpq-rjcx-7vj9. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

This affects the package clearance before 2.5.0. The vulnerability can be possible when users are able to set the value of `session[:return_to]`. If the value used for return_to contains multiple leading slashes (`/////example.com`) the user ends up being redirected to the external domain that comes after the slashes (`http://example.com`).

O3 Security · Impact-Aware SCA

Is GHSA-4hpq-rjcx-7vj9 in your dependencies?

O3 detects GHSA-4hpq-rjcx-7vj9 across RubyGems dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

Scan my dependencies How O3 SCA works