Angular Stored XSS Vulnerability via SVG Animation, SVG URL and MathML Attributes

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

Angular is a development platform for building mobile and desktop web applications using TypeScript/JavaScript and other languages. Prior to 21.0.2, 20.3.15, and 19.2.17, A Stored Cross-Site Scripting (XSS) vulnerability has been identified in the Angular Template Compiler. It occurs because the compiler's internal security schema is incomplete, allowing attackers to bypass Angular's built-in security sanitization. Specifically, the schema fails to classify certain URL-holding attributes (e.g., those that could contain javascript: URLs) as requiring strict URL security, enabling the injection of malicious scripts. This vulnerability is fixed in 21.0.2, 20.3.15, and 19.2.17.

Source published

1 Dec 2025 22:35:59 UTC

Source modified

2 Jun 2026 13:00:31 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

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CVSS 4.0 · 8.5 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Angular is a development platform for building mobile and desktop web applications using TypeScript/JavaScript and other languages. Prior to 21.0.2, 20.3.15, and 19.2.17, A Stored Cross-Site Scripting (XSS) vulnerability has been identified in the Angular Template Compiler. It occurs because the compiler's internal security schema is incomplete, allowing attackers to bypass Angular's built-in security sanitization. Specifically, the schema fails to classify certain URL-holding attributes (e.g., those that could contain javascript: URLs) as requiring strict URL security, enabling the injection of malicious scripts. This vulnerability is fixed in 21.0.2, 20.3.15, and 19.2.17.

Source published

Dec 1, 2025, 10:35:59 PM (timezone not stated)

Source modified

Jun 2, 2026, 1:00:31 PM (timezone not stated)

Observed here

9 Nov 2026 07:04:35 UTC

Source terms

ENISA EUVD · source terms and attribution apply

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: euvd · ENISA EUVD · source terms and attribution apply. Source text is retained; field grouping and change labels are provided by ChangeIntel.

EUVD CVSS 4.0 · 8.5 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Angular is a development platform for building mobile and desktop web applications using TypeScript/JavaScript and other languages. Prior to 21.0.2, 20.3.15, and 19.2.17, A Stored Cross-Site Scripting (XSS) vulnerability has been identified in the Angular Template Compiler. It occurs because the compiler's internal security schema is incomplete, allowing attackers to bypass Angular's built-in security sanitization. Specifically, the schema fails to classify certain URL-holding attributes (e.g., those that could contain javascript: URLs) as requiring strict URL security, enabling the injection of malicious scripts. This vulnerability is fixed in 21.0.2, 20.3.15, and 19.2.17.

Source published

1 Dec 2025 23:15:53 UTC

Source modified

18 Oct 2026 18:10:00 UTC

Observed here

25 Oct 2026 03:17:36 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 4.0 · [email protected] · Secondary · 8.5 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CVSS 3.1 · [email protected] · Primary · 5.4 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

A **Stored Cross-Site Scripting ([XSS](https://angular.dev/best-practices/security#preventing-cross-site-scripting-xss))** vulnerability has been identified in the **Angular Template Compiler**. It occurs because the compiler's internal security schema is incomplete, allowing attackers to bypass Angular's built-in security sanitization. Specifically, the schema fails to classify certain URL-holding attributes (e.g., those that could contain [`javascript:` URLs](https://developer.mozilla.org/en-US/Web/URI/Reference/Schemes/javascript)) as requiring strict URL security, enabling the injection of malicious scripts. Additionally, a related vulnerability exists involving SVG animation elements (`<animate>`, `<set>`, `<animateMotion>`, `<animateTransform>`). The `attributeName` attribute on these elements was not properly validated, allowing attackers to dynamically target security-sensitive attributes like `href` or `xlink:href` on other elements. By binding `attributeName` to "href" and providing a `javascript:` URL in the `values` or `to` attribute, an attacker could bypass sanitization and execute arbitrary code. Attributes confirmed to be vulnerable include: * SVG-related attributes: (e.g., `xlink:href`), and various MathML attributes (e.g., `math|href`, `annotation|href`). * SVG animation `attributeName` attribute when bound to "href" or "xlink:href". When template binding is used to assign untrusted, user-controlled data to these attributes (e.g., `[attr.xlink:href]="maliciousURL"` or `<animate [attributeName]="'href'" [values]="maliciousURL">`), the compiler incorrectly falls back to a non-sanitizing context or fails to block the dangerous attribute assignment. This allows an attacker to inject a `javascript:URL` payload. Upon user interaction (like a click) on the element, or automatically in the case of animations, the malicious JavaScript executes in the context of the application's origin. ### Impact When exploited, this vulnerability allows an attacker to execute arbitrary code within the context of the vulnerable application's domain. This enables: * **Session Hijacking:** Stealing session cookies and authentication tokens. * **Data Exfiltration:** Capturing and transmitting sensitive user data. * **Unauthorized Actions:** Performing actions on behalf of the user. ### Patches - 19.2.17 - 20.3.15 - 21.0.2 ### Attack Preconditions * The victim's Angular application must render data derived from **untrusted input** (e.g., from a database or API) and bind it to one of the unsanitized URL attributes or the `attributeName` of an SVG animation element. * The victim must perform a **user interaction** (e.g., clicking) on the compromised element for the stored script to execute, or the animation must trigger the execution. ### Workarounds If you cannot upgrade, you can workaround the issue by ensuring that any data bound to the vulnerable attributes is never sourced from untrusted user input (e.g., database, API response, URL parameters). * **Avoid Affected Template Bindings:** Specifically avoid using template bindings (e.g., `[attr.xlink:href]="maliciousURL"`) to assign untrusted data to the vulnerable SVG/MathML attributes. * **Avoid Dynamic `attributeName` on SVG Animations:** Do not bind untrusted data to the `attributeName` attribute of SVG animation elements (`<animate>`, `<set>`, etc.). * **Enable [Content Security Policy (CSP)](https://angular.dev/best-practices/security#content-security-policy):** Configure a robust CSP header that disallows `javascript:` URLs.

Source published

2 Dec 2025 01:20:30 UTC

Source modified

10 Sep 2026 03:50:32 UTC

Observed here

24 Oct 2026 13:17:17 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V4 · CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Publisher rating · HIGH