# CVE-2026-126208: Loofah: SVG `` and `` bypass local-reference restriction > Attackers can bypass Loofah's SVG local-reference restriction to make viewers fetch attacker-chosen URLs, leaking viewer network information. - **Severity:** Medium 4.7 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:N/A:N`) - **Exploited in the wild:** Not known - **Login needed:** Not needed - **Attackable:** Over the internet - **Victim action needed:** A user has to click or open something - **Harmful if only installed:** No - **Needs a specific call:** No - **Fix available:** Yes - **Published:** 12 Nov 2026 - **Updated:** 12 Nov 2026 - **Also known as:** GHSA-345x-3rq2-jfrm ## What is CVE-2026-126208? CVE-2026-126208 is a medium-severity security feature bypass vulnerability in flavorjones loofah, published on 12 Nov 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link. ### Official description Loofah is a general library for manipulating and transforming HTML/XML documents and fragments, built on top of Nokogiri. Prior to 2.25.3, Loofah's SVG_ALLOW_LOCAL_HREF safelist lists textPath with lowercase spelling that does not match the HTML5 parser's element name and omits mpath, so external href and xlink:href values on those elements survive sanitization. Firefox fetches the attacker-chosen URL when a viewer renders the content, which can disclose the viewer's IP address, user agent, referrer, and access to hosts routable only from the viewer's network. Chrome and WebKit do not fetch these references, and the impact is a network request rather than script execution. The rails-html-sanitizer PermitScrubber reuses the affected safelist when SVG elements are permitted. This issue is fixed in version 2.25.3. Weakness: CWE-184 (Incomplete List of Disallowed Inputs), CWE-178 (Improper Handling of Case Sensitivity) ## Which versions are affected by CVE-2026-126208? 1 open source package ship an affected version, including loofah. An affected version is exposed as installed. No special setting or call is needed. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `loofah` | RubyGems | All versions | 2.25.3 | ## How do I fix CVE-2026-126208? Upgrade loofah to 2.25.3 or later. ## Is CVE-2026-126208 being exploited? There is no known exploitation of CVE-2026-126208 in the wild and no public exploit code. ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2026-126208 and fix it if it is affected. What it is: CVE-2026-126208 is a medium-severity security feature bypass vulnerability in flavorjones loofah, published on 12 Nov 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link. Exploitation: There is no known exploitation of CVE-2026-126208 in the wild and no public exploit code. Exposure: An affected version is exposed as installed. No special setting or call is needed. Affected packages and fixed versions: - loofah (RubyGems): affected all versions; fixed in 2.25.3 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-2026-126208/ (Markdown: https://insights.sbomify.com/CVE-2026-126208/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2026-126208 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-126208 - OSV: https://osv.dev/vulnerability/CVE-2026-126208 --- From sbomify Insights: https://insights.sbomify.com/CVE-2026-126208/ Summaries are generated and may contain mistakes; the official description above is the record.