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MEDIUM severity

GHSA-jp5v-5gx4-jmj9

MEDIUM

GHSA-jp5v-5gx4-jmj9 is a medium-severity (CVSS 4.3) vulnerability in actionpack. 1 public exploit reference exists, so weaponization risk is real. O3 Security confirms whether GHSA-jp5v-5gx4-jmj9 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.

Ability to forge per-form CSRF tokens in Rails

Also known asCVE-2020-8166
Published
May 26, 2020
Updated
May 5, 2026
Affected
2 pkgs
Patched
2 / 2
Exploits
1 known
Exploitation data as of May 5, 2026 · OSV.dev, FIRST.org (EPSS)

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 GHSA-jp5v-5gx4-jmj9.

Real-World Exposure

2 pkgs affected
💎actionpack💎actionpack

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

It is possible to, given a global CSRF token such as the one present in the authenticity_token meta tag, forge a per-form CSRF token for any action for that session.

Impact

Given the ability to extract the global CSRF token, an attacker would be able to construct a per-form CSRF token for that session.

Workarounds

This is a low-severity security issue. As such, no workaround is necessarily until such time as the application can be upgraded.

Affected Packages

2 total 2 fixed
EcosystemPackageVulnerable rangeFix
💎RubyGemsactionpack5.0.0&&< 5.2.4.35.2.4.3
💎RubyGemsactionpack6.0.0&&< 6.0.3.16.0.3.1
Exploits & PoCs
1

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 dependency
  1. Detect

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

  2. Fix

    Update actionpack to 5.2.4.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-jp5v-5gx4-jmj9 is resolved across your whole dependency graph.

  3. 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.

  4. How O3 protects you

    O3 pinpoints whether GHSA-jp5v-5gx4-jmj9 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-jp5v-5gx4-jmj9. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Frequently Asked Questions

It is possible to, given a global CSRF token such as the one present in the authenticity_token meta tag, forge a per-form CSRF token for any action for that session. Impact ------ Given the ability to extract the global CSRF token, an attacker would be able to construct a per-form CSRF token for that session. Workarounds ----------- This is a low-severity security issue. As such, no workaround is necessarily until such time as the application can be upgraded.
O3 Security · Impact-Aware SCA

Is GHSA-jp5v-5gx4-jmj9 in your dependencies?

O3 detects GHSA-jp5v-5gx4-jmj9 across RubyGems dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.