PT-2026-27254 · Rubygems+1 · Action Pack+1

John Hawthorn · Published 2026-03-23 · Updated 2026-03-24 · CVE-2026-33167

Positive Technologies (AI Summary)

CVSS v4.0

1.3

Low

Base vector

AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:U

Name of the Vulnerable Software and Affected Versions Action Pack versions prior to 8.1.2.1

Description Action Pack, a Rubygem for building web applications on the Rails framework, has an issue where the debug exceptions page does not properly escape exception messages. A crafted exception message could inject arbitrary HTML and JavaScript into the page, potentially leading to Cross-Site Scripting (XSS). This impacts applications with detailed exception pages enabled (config.consider all requests local = true), which is the default in development.

Recommendations Update to Action Pack version 8.1.2.1 or later.

Exploit

Fix

XSS

Weakness Enumeration

CWE-79

Related Identifiers

CVE-2026-33167

GHSA-PGM4-439C-5JP6

Affected Products

Action Pack

Rails

References · 14

• 🔥 https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/33xxx/CVE-2026-33167.json · Exploit
• 🔥 https://github.com/rubysec/ruby-advisory-db/blob/master/gems/actionpack/CVE-2026-33167.yml · Exploit
• https://nvd.nist.gov/vuln/detail/CVE-2026-33167 · Security Note
• https://cve.org/CVERecord?id=CVE-2026-33167 · Security Note
• https://osv.dev/vulnerability/CVE-2026-33167 · Vendor Advisory
• https://osv.dev/vulnerability/GHSA-pgm4-439c-5jp6 · Vendor Advisory
• https://osv.dev/vulnerability/UBUNTU-CVE-2026-33167 · Vendor Advisory
• https://ubuntu.com/security/CVE-2026-33167 · Vendor Advisory
• https://github.com/rails/rails · Note
• https://github.com/rails/rails/releases/tag/v8.1.2.1 · Note
• https://github.com/rails/rails/security/advisories/GHSA-pgm4-439c-5jp6 · Note
• https://github.com/rails/rails/commit/6752711c8c31d79ba50d13af6a6698a3b85415e0 · Note
• https://twitter.com/VulmonFeeds/status/2036242294261576160 · Twitter Post
• https://twitter.com/cyberbivash/status/2036222511508029523 · Twitter Post