Threats / Rails / CVE-2019-5418
CVE-2019-5418
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-06-22
Rails Ruby on vulnerability
Ruby on Rails contains a path traversal vulnerability in Action View where specially crafted accept headers combined with render file: calls allow arbitrary file disclosure from the target server.
Verdict
Today item — known-exploited.
A remote attacker can exploit this vulnerability to read sensitive files on a Rails application server by manipulating HTTP accept headers in conjunction with render file: directives, potentially exposing configuration files, source code, or other confidential data.
01
Is it exploitable?
— the evidence, ranked above the scoreExploit available
Fully weaponized — public exploit code is cataloged for this vulnerability.We link the existence of the exploit; we do not host or redistribute payloads.
Reported exploitation
4 independent public reports of in-the-wild exploitation are cataloged.Distinct reporting sources (vendor, incident response, government); open them for the underlying claims.
Exploited in the wild
Listed in the CISA Known Exploited Vulnerabilities catalog (added 2025-07-07).
Probability (EPSS)
EPSS 0.98507 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
Affected: Rails, Ruby on Rails. Confirm exact fixed builds in the vendor advisory.
Weakness (CWE)
Mapped to CWE-22 Path Traversal — weakness family: Path traversal / file.CWE assignment from the public NVD record; the weakness class drives how the flaw is exploited.
02
Who’s exploiting it?
— attribution turns risk into urgencyAttribution not established
No confirmed (advisory-backed) threat-actor attribution is established for this record. Absence of a named actor is not absence of compromise — see Coverage & confidence.
03
Why it matters
— the attack path, told twice: adversary, then board1
Front door — unauthenticated access narrative 1
Attacker
I craft HTTP requests with malicious accept headers targeting a Rails application that uses render file: in its views.
Business
Sensitive files including credentials, private keys, and source code are exposed to unauthorized access.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I enumerate the server filesystem by systematically testing different file paths through the path traversal mechanism.
Business
Complete application architecture and infrastructure details become visible to the attacker, enabling further targeted attacks.
3
Lateral reach — past segmentation narrative 3
Attacker
I extract configuration files and environment variables that contain database credentials and API keys.
Business
Backend systems and third-party integrations are compromised, leading to data breach and lateral movement within the infrastructure.
04
What to do
— defensible action- Remediate per the vendor advisory — confirm the fixed build for your version and verify exposure.1
Say it to the boardA vulnerability with this evidence profile is a defensible budget line, not a backlog ticket — fund the change against the proof above.
05