CVE-2025-27219: cgi DoS (CVSS 5.8)

Description

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.

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CVSS v3.1 Score

5.8

MEDIUM

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

Weakness Type (CWE)

CWE-770 CWE-770

Affected Products

Vendor	Product	Versions
ruby-lang	cgi	< 0.3.5.1
ruby-lang	cgi	0.4.0 — 0.4.2
ruby-lang	cgi	All

References

Other References

https://github.com/rubysec/ruby-advisory-db/blob/master/gems/cgi/CVE-2025-27219.yml https://hackerone.com/reports/2936778 https://lists.debian.org/debian-lts-announce/2025/03/msg00008.html

Frequently Asked Questions

What is CVE-2025-27219? +

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. It has a CVSS v3.1 base score of 5.8 (MEDIUM).

How severe is CVE-2025-27219? +

CVE-2025-27219 has a CVSS v3.1 score of 5.8 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2025-27219? +

CVE-2025-27219 affects products from ruby-lang, specifically: cgi. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-27219? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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CVE-2025-27219