# CVE-2026-126078: Action View: Possible XSS vulnerability in Action View highlight helper

Status: published. Published: 2026-11-10. Updated: 2026-11-12.

Action View is a framework for handling view template lookup and rendering and provides view helpers for building HTML. Prior to 8.1.4.1 and 8.0.5.2, ActionView::Helpers::TextHelper#highlight substitutes each matched phrase into the :highlighter string without escaping it and returns the result marked HTML-safe. Because sanitizing leaves quote characters in text unescaped, a match substituted into a quoted attribute value of the highlighter, such as the <a href="search?q=\1"> form shown in the method's documentation, could end the attribute value and add attributes to the element, possibly leading to XSS. Applications are affected when they pass a :highlighter that places a placeholder inside an attribute value and highlight text or phrases that a user controls. The default <mark>\1</mark> highlighter and the block form are not affected. This issue is fixed in versions 8.1.4.1 and 8.0.5.2.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- rails / rails: < 8.0.5.2 (affected); >= 8.1, < 8.1.4.1 (affected). Source: CNA: GitHub_M

## Severity and prioritization

- CVSS 3.1: 6.1 (medium); CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N; source: CNA: GitHub_M

- CVSS 3.1: 6.1 (medium); CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N; source: NVD: security-advisories@github.com

- CISA KEV: No listing in collected sources

- EPSS: 0.34% as of 2026-11-12; percentile 27.57%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-79

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/rails/rails/security/advisories/GHSA-v6rj-xm57-3p59 (CNA: GitHub_M; x_refsource_CONFIRM)

- https://github.com/rails/rails/commit/06938194b4fd59e1d2c8ab4a781f3c1e2b763425 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/rails/rails/commit/c796f6198837479ada13290eb8fa767b5219a58a (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/rails/rails/releases/tag/v8.0.5.2 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/rails/rails/releases/tag/v8.1.4.1 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/rails/rails/commit/06938194b4fd59e1d2c8ab4a781f3c1e2b763425 (security-advisories@github.com)

- https://github.com/rails/rails/commit/c796f6198837479ada13290eb8fa767b5219a58a (security-advisories@github.com)

- https://github.com/rails/rails/releases/tag/v8.0.5.2 (security-advisories@github.com)

- https://github.com/rails/rails/releases/tag/v8.1.4.1 (security-advisories@github.com)

- https://github.com/rails/rails/security/advisories/GHSA-v6rj-xm57-3p59 (security-advisories@github.com)

## Provenance

- CNA: GitHub_M: https://www.cve.org/CVERecord?id=CVE-2026-126078; retrieved 2026-11-12; source updated 2026-11-12

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-126078; retrieved 2026-11-11; source updated 2026-11-10

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-126078; retrieved 2026-11-12; source updated Not reported

Revision: 03de155a1ae5cbe79a9ae601e1caefcb8d0d96e5f72262f8919caef2b70af00d

Canonical: https://y2.dev/cve/CVE-2026-126078

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