+44 1865 950 828 Secure Your Business
Actively exploited

CVE-2019-5418 Rails Ruby on Rails Path Traversal Vulnerability

Rails Ruby on Rails contains a path traversal vulnerability in Action View. Specially crafted accept headers in combination with calls to `render file:` can cause arbitrary files on the target server to be rendered, disclosing the file contents.

From the CISA KEV catalogue version 2026.11.06, with Cybergen analysis. Updated 6 Nov 2026.

Our Assessment

Should You Worry?

Patch urgentlyCybergen assessment
  • CISA confirmed exploitation in the wild and added it to the Known Exploited Vulnerabilities catalogue on 7 Jul 2025.
  • Rated High severity (CVSS 7.5, scored by CISA).
  • It has been in the catalogue for 487 days. Systems still unpatched now have almost certainly been scanned for it.
The Vulnerability

What It Is

There is a File Content Disclosure vulnerability in Action View <5.2.2.1, <5.1.6.2, <5.0.7.2, <4.2.11.1 and v3 where specially crafted accept headers can cause contents of arbitrary files on the target system's filesystem to be exposed.

Affected Versions

ProductVersions
Rails https://github.com/rails/rails5.2.2.1
5.1.6.2
5.0.7.2
4.2.11.1

From the public CVE record, as supplied by the vendor. Always confirm against the vendor advisory.

From Watch to Action

What To Do Now

  1. 1

    Find it

    Search your asset inventory and external attack surface for Rails Ruby on Rails. Include cloud images, appliances and anything a supplier runs for you.

    Attack Surface Management
  2. 2

    Fix it

    Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

    Vulnerability Management
  3. 3

    Hunt for compromise

    If an affected system was reachable before you patched, assume it may have been hit. Check logs, new accounts, web shells and outbound connections from the date of exposure.

    Incident Response
  4. 4

    Prove it is fixed

    Rescan or test the system after patching. Upgrades that fail silently and forgotten secondary instances are common.

    Penetration Testing

Vendor Advisories

Regulation

The Compliance Clock

Cyber EssentialsRated high, so if it affects devices in your Cyber Essentials scope, the update must be installed within 14 days of the vendor releasing it.NIS2If exploitation causes a significant incident, essential and important entities owe their CSIRT an early warning within 24 hours and a notification within 72 hours.DORAFinancial entities must classify ICT incidents and send an initial notification for a major incident within strict deadlines, with exploited flaws a common cause.US federal (BOD 22-01)Federal civilian agencies had until 28 Jul 2025 to remediate. A sensible benchmark for everyone else.

General guidance, not legal advice. Your obligations depend on your sector, scope and jurisdiction.

Stay Ahead

More Exploited Rails Flaws

Get alerts for RailsWe email you when a new Rails vulnerability is confirmed as exploited. Add more vendors on Threat Watch.

By signing up you agree to receive Threat Watch alerts. Unsubscribe at any time. See our Privacy Policy.

CVE-2016-0752Ruby on Rails Directory Traversal VulnerabilityAdded 25 Mar 2022CVE-2014-0130Ruby on Rails Directory Traversal VulnerabilityAdded 25 Mar 2022

All 3 exploited Rails vulnerabilities

Not Sure If You Are Exposed?

Our attack surface and vulnerability teams can check your internet-facing estate for CVE-2019-5418 and every other exploited flaw on the list.

Check My Exposure
Evidence

Sources

  1. CISA Known Exploited Vulnerabilities catalogue
  2. NVD: CVE-2019-5418
  3. CVE record: CVE-2019-5418
  4. FIRST EPSS
  5. web.archive.org/web/20190313201629/https://weblog.rubyonrails.org/2019/3/13/Rails-4-2-5-1-5-1-6-2-ha
  6. exploit-db.com/exploits/46585/
  7. packetstormsecurity.com/files/152178/Rails-5.2.1-Arbitrary-File-Content-Disclosure.html
  8. openwall.com/lists/oss-security/2019/03/22/1
  9. weblog.rubyonrails.org/2019/3/13/Rails-4-2-5-1-5-1-6-2-have-been-released/
  10. groups.google.com/forum/#%21topic/rubyonrails-security/pFRKI96Sm8Q
  11. lists.debian.org/debian-lts-announce/2019/03/msg00042.html
  12. access.redhat.com/errata/RHSA-2019:0796