# CVE-2026-126078: Action View: Possible XSS vulnerability in Action View highlight helper - **Severity:** Medium 6.1 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N`) - **Exploited in the wild:** Not known - **Fix available:** Yes - **Published:** 10 Nov 2026 - **Updated:** 12 Nov 2026 - **Also known as:** DEBIAN-CVE-2026-126078, GHSA-v6rj-xm57-3p59, UBUNTU-CVE-2026-126078 ## What is CVE-2026-126078? CVE-2026-126078 is a medium-severity vulnerability in rails, published on 10 Nov 2026. ### Official description 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 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 \1 highlighter and the block form are not affected. This issue is fixed in versions 8.1.4.1 and 8.0.5.2. Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation) ## Which versions are affected by CVE-2026-126078? 2 open source packages ship an affected version, including actionview. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `actionview` | RubyGems | All versions | 8.0.5.2 | | `actionview` | RubyGems | From 8.1.0.beta1 | 8.1.4.1 | ## How do I fix CVE-2026-126078? Upgrade actionview to a fixed version for your release line: 8.0.5.2 or 8.1.4.1. ## Is CVE-2026-126078 being exploited? There is no known exploitation of CVE-2026-126078 in the wild and no public exploit code. ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2026-126078 and fix it if it is affected. What it is: CVE-2026-126078 is a medium-severity vulnerability in rails, published on 10 Nov 2026. Exploitation: There is no known exploitation of CVE-2026-126078 in the wild and no public exploit code. Affected packages and fixed versions: - actionview (RubyGems): affected all versions; fixed in 8.0.5.2 - actionview (RubyGems): affected from 8.1.0.beta1; fixed in 8.1.4.1 Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2026-126078/ (Markdown: https://insights.sbomify.com/CVE-2026-126078/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2026-126078 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-126078 - OSV: https://osv.dev/vulnerability/CVE-2026-126078 --- From sbomify Insights: https://insights.sbomify.com/CVE-2026-126078/ Summaries are generated and may contain mistakes; the official description above is the record.