Vulnerability · Published Mar 23, 2026 · Assigned by GitHub_M
CVE-2026-33167Rails has a possible XSS vulnerability in its Action Pack debug exceptions
Low 1.3
In plain English
A low-severity cross-site scripting in actionpack from rails. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 18% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
Action Pack is a Rubygem for building web applications on the Rails framework. In versions on the 8.1 branch prior to 8.1.2.1, the debug exceptions page does not properly escape exception messages. A carefully crafted exception message could inject arbitrary HTML and JavaScript into the page, leading to XSS. This affects applications with detailed exception pages enabled (`config.consider_all_requests_local = true`), which is the default in development. Version 8.1.2.1 contains a patch.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| RubyGems | actionpack | 8.1.2.1 | GHSA-pgm4-439c-5jp6 |
| Ubuntu:24.04:LTS | rails | no fix listed | UBUNTU-CVE-2026-33167 |
| Ubuntu:25.10 | rails | no fix listed | UBUNTU-CVE-2026-33167 |
| Ubuntu:26.04:LTS | rails | no fix listed | UBUNTU-CVE-2026-33167 |
| Ubuntu:26.10 | rails | no fix listed | UBUNTU-CVE-2026-33167 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| rails | actionpack | >= 8.1.0, < 8.1.2.1 |
Weakness: CWE-79 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:U
References
- https://github.com/rails/rails/security/advisories/GHSA-pgm4-439c-5jp6 x_refsource_CONFIRM
- https://github.com/rails/rails/commit/6752711c8c31d79ba50d13af6a6698a3b85415e0 x_refsource_MISC
- https://github.com/rails/rails/releases/tag/v8.1.2.1 x_refsource_MISC