Skip to content
Fencer Vulns
medium 5.8

CVE-2025-27219 json

CGI has Denial of Service (DoS) potential in Cookie.parse

published 2025-03-03 20 mo ago modified 2026-09-10 1 mo ago also EUVD-2025-5556 , GHSA-gh9q-2xrm-x6qv

cvss
5.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.8%
EPSS 0.8% chance of exploitation in 30 days, percentile 58%
public exploits
0
none known

Summary

In the CGI gem before 0.4.2 for Ruby, the CGI::Cookie.parse method in the CGI library contains a potential Denial of Service (DoS) vulnerability. The method does not impose any limit on the length of the raw cookie value it processes. This oversight can lead to excessive resource consumption when parsing extremely large cookies.

Patch / fix

  • rubygems cgi 0.3.5.1, 0.3.7, 0.4.2
  • ruby-lang CGI 0.3.5.1, 0.3.7, 0.4.2
  • ruby3.3 Debian 14, Debian 13 3.3.7-2

debian advisories DEBIAN-CVE-2025-27219

  • ruby2.7 Ubuntu 20.04 LTS 2.7.0-5ubuntu1.18
  • ruby3.0 Ubuntu 22.04 LTS 3.0.2-7ubuntu2.10
  • ruby3.2 Ubuntu 24.04 LTS 3.2.3-1ubuntu0.24.04.5
  • ruby3.3 Ubuntu 25.10 3.3.7-1ubuntu2
  • ruby2.3 Ubuntu Pro 16.04 LTS 2.3.1-2~ubuntu16.04.16+esm10
  • ruby2.5 Ubuntu Pro 18.04 LTS 2.5.1-1ubuntu1.16+esm4

ubuntu advisories UBUNTU-CVE-2025-27219

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

  • ruby RHEL 8 3.3.8-4.module+el8.10.0+23024+a87ba659
  • rubygems RHEL 8 3.5.22-4.module+el8.10.0+23024+a87ba659
  • ruby-libs RHEL 8 3.3.8-4.module+el8.10.0+23024+a87ba659
  • rubygem-pg RHEL 8 1.5.4-1.module+el8.10.0+21226+b78a28c4
  • rubygem-irb RHEL 8 1.13.1-4.module+el8.10.0+23024+a87ba659
  • rubygem-rbs RHEL 8 3.4.0-4.module+el8.10.0+23024+a87ba659
  • rubygem-rss RHEL 8 0.3.1-4.module+el8.10.0+23024+a87ba659
  • rubygem-abrt RHEL 8 0.4.0-1.module+el8.10.0+21226+b78a28c4

red hat advisories RHSA-2025:10217RHSA-2025:8131RHSA-2025:4493RHSA-2025:4488RHSA-2025:4487RHSA-2025:4063

  • ruby2.5 SLE Module for Basesystem 15 SP7 2.5.9-150700.24.3.1
  • ruby2.5 SLES for SAP 15 SP5, SLES for SAP 15 SP4, SLES for SAP 15 SP3 +13 more 2.5.9-150000.4.41.1

suse advisories SUSE-SU-2025:4264-1SUSE-SU-2025:1369-1

  • ruby AlmaLinux 8 3.3.8-4.module_el8.10.0+4022+8b66723c
  • rubygems AlmaLinux 8 3.5.22-4.module_el8.10.0+4022+8b66723c
  • ruby-libs AlmaLinux 8 3.3.8-4.module_el8.10.0+4022+8b66723c
  • rubygem-pg AlmaLinux 8 1.5.4-1.module_el8.10.0+3799+191214cc
  • rubygem-irb AlmaLinux 8 1.13.1-4.module_el8.10.0+4022+8b66723c
  • rubygem-rbs AlmaLinux 8 3.4.0-4.module_el8.10.0+4022+8b66723c
  • rubygem-rss AlmaLinux 8 0.3.1-4.module_el8.10.0+4022+8b66723c
  • rubygem-abrt AlmaLinux 8 0.4.0-1.module_el8.10.0+3799+191214cc

almalinux advisories ALSA-2025:10217ALSA-2025:8131ALSA-2025:4488ALSA-2025:4063

  • ruby Rocky Linux 10 3.3.8-10.el10_0
  • ruby Rocky Linux 9 3.1.7-146.module+el9.5.0+31847+8b291b93
  • rubygem-pg Rocky Linux 9 1.3.5-1.module+el9.5.0+31847+8b291b93
  • rubygem-mysql2 Rocky Linux 9 0.5.4-1.module+el9.5.0+31847+8b291b93
  • ruby Rocky Linux 9 3.3.8-4.module+el9.6.0+31867+3a5bf654
  • rubygem-pg Rocky Linux 9 1.5.4-1.module+el9.6.0+31867+3a5bf654
  • rubygem-mysql2 Rocky Linux 9 0.5.5-1.module+el9.6.0+31867+3a5bf654
  • ruby Rocky Linux 9 3.0.7-165.el9_5

rocky linux advisories RLSA-2025:8131RLSA-2025:4488RLSA-2025:4493RLSA-2025:4487RLSA-2025:10217RLSA-2025:4063

  • ruby Alpine 3.19 3.2.8-r0
  • ruby Alpine 3.21, Alpine 3.20 3.3.8-r0
  • ruby-net-imap Alpine 3.19 0.3.9-r0
  • ruby-net-imap Alpine 3.21, Alpine 3.20 0.4.19-r0

alpine advisories ALPINE-CVE-2025-27219

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • ruby CBL-Mariner 2.0 3.1.4-9
  • ruby Azure Linux 3.0 3.3.5-3

azure linux advisories AZL-57828AZL-57923

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

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-2025-27219 updated cvss 5.3

CGI: Denial of Service in CGI::Cookie.parse

  • Red Hat Enterprise Linux 6 ruby, ruby-ri, ruby-irb, ruby-libs, ruby-rdoc, ruby-tcltk Red Hat Enterprise Linux 7 ruby, ruby-irb, rubygems, ruby-libs, ruby-tcltk, rubygem-json, +6 more Red Hat Enterprise Linux 8 ruby, ruby-irb, rubygems, ruby-libs, rubygem-pg, rubygem-irb, +25 more
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat CodeReady Linux Builder (v. 9) ruby-doc 3.0.7-165.el9_5
    fixed: vendor fix RHSA-2025:4487
  • Red Hat Enterprise Linux AppStream (v. 8) ruby 3.3.8-4.module+el8.10.0+23024+a87ba659, ruby 3.1.7-145.module+el8.10.0+23011+f9d508f8, ruby-libs 3.3.8-4.module+el8.10.0+23024+a87ba659, rubygems 3.5.22-4.module+el8.10.0+23024+a87ba659, rubygem-pg 1.3.2-1.module+el8.10.0+21470+43ec8058, rubygem-pg 1.5.4-1.module+el8.10.0+21226+b78a28c4, +41 more
    fixed: vendor fix RHSA-2025:4063
  • Red Hat Enterprise Linux AppStream (v. 9) ruby 3.0.7-165.el9_5, ruby-libs 3.0.7-165.el9_5, rubygems 3.2.33-165.el9_5, rubygem-irb 1.3.5-165.el9_5, rubygem-rbs 1.4.0-165.el9_5, rubygem-rss 0.2.9-165.el9_5, +58 more
    fixed: vendor fix RHSA-2025:4487
  • Red Hat Enterprise Linux AppStream (v. 10) ruby 3.3.8-10.el10_0, ruby-libs 3.3.8-10.el10_0, rubygems 3.5.22-10.el10_0, rubygem-rbs 3.4.0-10.el10_0, rubygem-rss 0.3.1-10.el10_0, rubygem-irb 1.13.1-10.el10_0, +15 more Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) ruby-doc 3.3.8-10.el10_0
    fixed: vendor fix RHSA-2025:8131

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

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
20 mo ago

Exploit prediction

0.85% chance of exploitation in the next 30 days, higher than 58% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 5.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L
GitHub 3.1 5.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
rubygems cgi
<0.3.5.1
>=0.3.6, <0.3.7
>=0.4.0, <0.4.2
0.3.5.1
0.3.7
0.4.2

Affected products

  • ruby-lang CGI

Classification

Weakness
  • CWE-770 Allocation of Resources Without Limits or Throttling
  • CWE-400 Uncontrolled Resource Consumption

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.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.