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Fencer Vulns
high 8.8

CVE-2017-11173 json

Missing Regex anchor in Rack-Cors allows malicious third party site to perform CORS request

published 2017-07-13 9 y ago modified 2026-06-17 4 mo ago also GHSA-2j9c-9vmv-7m39 , EUVD-2018-0207

cvss
8.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
2.3%
EPSS 2.3% chance of exploitation in 30 days, percentile 83%
public exploits
0
none known

Summary

Missing anchor in generated regex for rack-cors before 0.4.1 allows a malicious third-party site to perform CORS requests. If the configuration were intended to allow only the trusted example.com domain name and not the malicious example.net domain name, then example.com.example.net (as well as example.com-example.net) would be inadvertently allowed.

Patch / fix

  • rubygems rack-cors 0.4.1
  • rack-cors_project rack-cors 0.4.1
  • ruby-rack-cors Debian 14, Debian 13, Debian 12 0.4.1-1

debian advisories DEBIAN-CVE-2017-11173

  • ruby-rack-cors Ubuntu 16.04 LTS 0.4.0-1+deb9u1build0.16.04.1

ubuntu advisories UBUNTU-CVE-2017-11173

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

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-2017-11173 updated cvss 4.8

rubygem-rack-cors: Missing anchor in generated regex in rack/cors.rb#L256 may permit forged malicious requests

  • 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

2.34% chance of exploitation in the next 30 days, higher than 83% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
NVD 2.0 6.8 AV:N/AC:M/Au:N/C:P/I:P/A:P
GitHub 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
rubygems rack-cors
<0.4.1
0.4.1

References

Sources

Fencer Vulns 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.