Skip to content
Fencer Intel
medium 5.3

CVE-2019-18978 json

The rack-cors rubygem may allow directory traveral

published 6y ago modified 4mo ago also GHSA-pf8f-w267-mq2h , EUVD-2019-0758

cvss
5.3
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
2.5%
EPSS 2.5% chance of exploitation in 30 days, percentile 84%
public exploits
0
none known

Summary

An issue was discovered in the rack-cors (aka Rack CORS Middleware) gem before 1.0.4 for Ruby. It allows ../ directory traversal to access private resources because resource matching does not ensure that pathnames are in a canonical format.

Patch / fix

  • rubygems rack-cors 1.0.4
  • rack-cors_project rack-cors 1.0.4
  • ruby-rack-cors Debian 14, Debian 13, Debian 12 1.1.1-1

debian advisories DEBIAN-CVE-2019-18978

  • ruby-rack-cors Ubuntu 16.04 LTS 0.4.0-1+deb9u2build0.16.04.1

ubuntu advisories UBUNTU-CVE-2019-18978

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Is CVE-2019-18978 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

Check with Fencer

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2019-18978 updated cvss 5.3

rubygem-rack-cors: allows ../ directory traversal to access private resources

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

2.46% chance of exploitation in the next 30 days, higher than 84% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
NVD 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:P/I:N/A:N
GitHub 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Affected packages

ecosystem package affected fixed in
rubygems rack-cors
<1.0.4
1.0.4

Classification

Weakness
  • CWE-22 Improper Limitation of a Pathname to a Restricted Directory

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.