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CVE-2019-18978

21
FAUCET Score

CVE-2019-18978 is a directory traversal vulnerability in the rack-cors gem (versions prior to 1.0.4) for Ruby, affecting various Canonical and Debian Linux distributions. This medium-severity vulnerability (CVSS 5.3) allows an unauthenticated attacker to access private resources by manipulating pathnames. While there is no known active exploitation or public exploit code (Metasploit, Nuclei, ExploitDB), the vulnerability has received minimal community discussion and media coverage, with one article mentioning it in a GitLab security release.

Impacted Technologies

VendorProductVersion(s)CPE
< 1.0.4CPE matchmatch criteria
cpe:2.3:a:rack-cors_project:rack-cors:*:*:*:*:*:ruby:*:*
8.0CPE matchmatch criteria
cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:*
9.0CPE matchmatch criteria
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
10.0CPE matchmatch criteria
cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*
16.04CPE matchmatch criteria
cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:esm:*:*:*

CVSS Data

CVSS version used by this source: 3.1

5.3MEDIUM

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
LOW
Integrity Impact
NONE
Availability Impact
NONE
Exploitability Score
3.9
Impact Score
1.4
CvssVersion
3.1

Exploit Intelligence

EPSS Score
2.46%
Probability of exploitation in next 30 days
EPSS Percentile
82.8%
Percentile rank of EPSS score among Peer Group
As of 2026-07-25
Model: v2026.06.15
This CVE's current EPSS score of 0.0246 is in the 74th percentile among its peer group of 23,701 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.0 Mastodon, and 0.4 GitHub mentions.

Media Mentions

The average CVE in this peer group has 0.0 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (2)

github_advisorypatch availablevia nvd_reference
View patch
rubygemspatch availablevia ghsa
Product: rack-corsFixed in: 1.0.4

Vendor Advisories (1)

rubygemsGHSA-pf8f-w267-mq2hmedium

The rack-cors rubygem may allow directory traveral

Nov 15, 2019

References

github.com / cyu/rack-cors/commit/e4d4fc362a4315808927011cbe5afcfe5486f17d
PatchThird Party Advisory
github.com / cyu/rack-cors/compare/v1.0.3...v1.0.4
PatchThird Party Advisory
lists.debian.org / debian-lts-announce/2020/02/msg00004.html
Mailing ListThird Party Advisory
lists.debian.org / debian-lts-announce/2020/10/msg00000.html
Mailing ListThird Party Advisory
usn.ubuntu.com / 4571-1
Third Party Advisory
debian.org / security/2021/dsa-4918
Third Party Advisory