How severe is GHSA-gxx4-3xcv-f8qx?

No CVSS score has been assigned to GHSA-gxx4-3xcv-f8qx yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by GHSA-gxx4-3xcv-f8qx?

GHSA-gxx4-3xcv-f8qx affects the following packages: @angular/platform-server (npm), @angular/platform-server (npm), @angular/platform-server (npm), @angular/platform-server (npm), @angular/platform-server (npm). Ecosystems affected: npm.

How do I fix GHSA-gxx4-3xcv-f8qx?

Update @angular/platform-server to 22.0.0-rc.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-gxx4-3xcv-f8qx is resolved across your whole dependency graph.

How do I detect GHSA-gxx4-3xcv-f8qx in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @angular/platform-server, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate GHSA-gxx4-3xcv-f8qx if there is no patch (or I can't update yet)?

Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Is GHSA-gxx4-3xcv-f8qx actively exploited in the wild?

No public exploit code has been indexed for GHSA-gxx4-3xcv-f8qx yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for GHSA-gxx4-3xcv-f8qx?

GHSA-gxx4-3xcv-f8qx has an EPSS (Exploit Prediction Scoring System) score of 0.4%, placing it in the 33th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is GHSA-gxx4-3xcv-f8qx?

GHSA-gxx4-3xcv-f8qx is classified as Cross-site Scripting (XSS) (CWE-79). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was GHSA-gxx4-3xcv-f8qx published, and has it been updated?

GHSA-gxx4-3xcv-f8qx was published on June 15, 2026 and was last updated on September 10, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

📦 npm

Not in CISA KEV

GHSA-gxx4-3xcv-f8qx — @angular/platform-server

Fix: angular/domino#29

GHSA-gxx4-3xcv-f8qx is a Cross-site Scripting (XSS) vulnerability in @angular/platform-server. A fix is available for @angular/platform-server — see the affected versions and patch details below.

@angular/platform-server: Missing `<noscript>` Raw-Text Serialization Escaping leads to Cross-Site Scripting (XSS) in Angular SSR

Also known asCVE-2026-50556

Published

Jun 15, 2026

Updated

Sep 10, 2026

Affected

5 pkgs

Patched

4 / 5

Exploits

None indexed

Exploitation data as of Sep 27, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

A successful exploit gives an attacker total control of the affected component, not partial access.
CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for GHSA-gxx4-3xcv-f8qx.

EPSS Exploitation Probability

via FIRST.org ↗

0.4%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs33th percentile — riskier than 33% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

5 pkgs affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

1Kother npm packages depend on this — each one inherits the vulnerability until it's patched upstream

@angular/platform-servernpm

896Kdownloads / week

Description

A Cross-Site Scripting (XSS) vulnerability exists in @angular/platform-server's DOM emulation dependency (domino) when serializing the content of <noscript> elements.

When rendering dynamic text content inside a <noscript> element via template bindings (such as {{ value }} or [textContent]), the template engine expects the browser to render the content safely. Under Server-Side Rendering (SSR), domino is configured with scripting enabled, meaning <noscript> is treated as a raw-text element.

However, domino's serializer completely omitted <noscript> from the list of raw-text elements requiring closing-tag escaping during DOM serialization. As a result, any occurrence of </noscript> in the bound dynamic text was never escaped under any circumstances.

The unescaped closing tag was serialized directly into the output HTML (e.g. <noscript></noscript><script>alert(1)</script></noscript>). When parsed by a browser, it closes the <noscript> block early, allowing the injected <script> block to execute in the user's browser context, causing same-origin Cross-Site Scripting (XSS).

Impact

This vulnerability allows an attacker to perform same-origin Cross-Site Scripting (XSS) attacks against any user visiting an SSR-rendered page that binds user-controlled data inside a <noscript> element. This can lead to session hijacking, credentials theft, unauthorized actions on behalf of users, and defacement.

Patched Versions

22.0.0-rc.2
21.2.16
20.3.24
19.2.25

Workarounds

If you cannot immediately update your dependencies, you can:

Avoid binding user-controlled values inside <noscript> elements.
Sanitize any user input placed inside <noscript> to explicitly strip closing </noscript> tags before passing it to the template.

Affected Packages

5 total 4 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`@angular/platform-server`	≥ 22.0.0-next.0&&< 22.0.0-rc.2	22.0.0-rc.2`npm install @angular/platform-server@22.0.0-rc.2`
📦npm	`@angular/platform-server`	≥ 21.0.0-next.0&&< 21.2.16	21.2.16`npm install @angular/platform-server@21.2.16`
📦npm	`@angular/platform-server`	≥ 20.0.0-next.0&&< 20.3.24	20.3.24`npm install @angular/platform-server@20.3.24`
📦npm	`@angular/platform-server`	≥ 19.0.0-next.0&&< 19.2.25	19.2.25`npm install @angular/platform-server@19.2.25`
📦npm	`@angular/platform-server`	all versions	No fix

Affected Products

1 product · 19 configurations

Application

angularangular

≥ 21.0.0 && ≤ 18.2.14

1 version

22.0.0

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @angular/platform-server, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update @angular/platform-server to 22.0.0-rc.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-gxx4-3xcv-f8qx is resolved across your whole dependency graph.
Workarounds
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatImportant

This flaw has an Important impact as @angular/platform-server's DOM emulation dependency (domino) in Red Hat products does not properly escape closing noscript tags during server-side rendering. A remote unauthenticated attacker can inject a crafted closing noscript tag into dynamic text content, which is serialized…

Workaround published by Red Hat

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.

Source: Red Hat security advisory for GHSA-gxx4-3xcv-f8qx (CC BY 4.0)

Frequently Asked Questions

A Cross-Site Scripting (XSS) vulnerability exists in `@angular/platform-server`'s DOM emulation dependency (`domino`) when serializing the content of `<noscript>` elements. When rendering dynamic text content inside a `<noscript>` element via template bindings (such as `{{ value }}` or `[textContent]`), the template engine expects the browser to render the content safely. Under Server-Side Rendering (SSR), `domino` is configured with scripting enabled, meaning `<noscript>` is treated as a raw-text element. However, `domino`'s serializer completely omitted `<noscript>` from the list of raw-te

O3 Security · Impact-Aware SCA

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