Summaryinfo

A vulnerability, which was classified as problematic, has been found in rails activesupport. This impacts the function html_unsafe. Performing a manipulation results in cross site scripting. This vulnerability is reported as CVE-2026-33170. The attack is possible to be carried out remotely. No exploit exists. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability classified as problematic has been found in rails activesupport. This affects the function html_unsafe. The manipulation with an unknown input leads to a cross site scripting vulnerability. CWE is classifying the issue as CWE-79. The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. This is going to have an impact on integrity. The summary by CVE is:

Active Support is a toolkit of support libraries and Ruby core extensions extracted from the Rails framework. Prior to versions 8.1.2.1, 8.0.4.1, and 7.2.3.1, `SafeBuffer#%` does not propagate the `@html_unsafe` flag to the newly created buffer. If a `SafeBuffer` is mutated in place (e.g. via `gsub!`) and then formatted with `%` using untrusted arguments, the result incorrectly reports `html_safe? == true`, bypassing ERB auto-escaping and possibly leading to XSS. Versions 8.1.2.1, 8.0.4.1, and 7.2.3.1 contain a patch.

It is possible to read the advisory at github.com. This vulnerability is uniquely identified as CVE-2026-33170 since 03/17/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. It demands that the victim is doing some kind of user interaction. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1059.007 according to MITRE ATT&CK.

Upgrading to version 7.2.3.1, 8.0.4.1 or 8.1.2.1 eliminates this vulnerability. The upgrade is hosted for download at github.com. Applying the patch 50d732af3b7c8aaf63cbcca0becbc00279b215b7 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

Vendor

• rails

Name

• activesupport

License

• open-source

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CPE 2.2info

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