Severity by source
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/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
Primary rating from GitHub Advisory.
CVSS VectorGitHub Advisory
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/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
Lifecycle Timeline
5DescriptionGitHub Advisory
A Cross-Site Scripting (XSS) vulnerability has been identified in the Angular runtime and compiler. It occurs when the application uses a security-sensitive attribute (for example href on an anchor tag) together with Angular's ability to internationalize attributes. Enabling internationalization for the sensitive attribute by adding i18n-<attribute> name bypasses Angular's built-in sanitization mechanism, which when combined with a data binding to untrusted user-generated data can allow an attacker to inject a malicious script.
The following example illustrates the issue:
<a href="{{maliciousUrl}}" i18n-href>Click me</a>The following attributes have been confirmed to be vulnerable:
actionbackgroundcitecodebasedataformactionhrefitemtypelongdescpostersrcxlink:href
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.
Attack Preconditions
- The application must use a vulnerable version of Angular.
- The application must bind unsanitized user input to one of the attributes mentioned above.
- The bound value must be marked for internationalization via the presence of a
i18n-<name>attribute on the same element.
Patches
- 22.0.0-next.3
- 21.2.4
- 20.3.18
- 19.2.20
Workarounds
The primary workaround is to ensure that any data bound to the vulnerable attributes is never sourced from untrusted user input (e.g., database, API response, URL parameters) until the patch is applied, or when it is, it shouldn't be marked for internationalization.
Alternatively, users can explicitly sanitize their attributes by passing them through Angular's DomSanitizer:
import {Component, inject, SecurityContext} from '@angular/core';
import {DomSanitizer} from '@angular/platform-browser';
@Component({
template: `
<form action="{{url}}" i18n-action>
<button>Submit</button>
</form>
`,
})
export class App {
url: string;
constructor() {
const dangerousUrl = 'javascript:alert(1)';
const sanitizer = inject(DomSanitizer);
this.url = sanitizer.sanitize(SecurityContext.URL, dangerousUrl) || '';
}
}AnalysisAI
A Cross-Site Scripting (XSS) vulnerability in Angular's runtime and compiler allows attackers to bypass built-in sanitization when internationalization (i18n) is enabled on security-sensitive attributes like href, src, and action. The vulnerability affects Angular versions before 19.2.20, 20.3.18, 21.2.4, and 22.0.0-next.3, enabling attackers with low privileges to execute arbitrary JavaScript in users' browsers for session hijacking, data theft, and unauthorized actions. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Angular application must: (1) use `i18n-<attribute>` directive on security-sensitive attributes (href, src, onclick, etc.), (2) bind those attributes to untrusted user-generated data via Angular data binding, (3) lack additional output encoding. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 4.0 score of 8.6 reflects high potential impact (VC:H/VI:H/VA:H) with network-based attacks requiring low privileges and passive user interaction. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker submits malicious JavaScript URLs through a user profile form where the application stores and displays user-provided website links using <a href='{{userWebsite}}' i18n-href>Visit Website</a>. When other users view the profile, the malicious JavaScript executes in their browser context, allowing the attacker to steal session cookies and perform actions as the victim user. … |
| Remediation | Upgrade Angular to patched versions immediately: 19.2.20 or later for v19 users, 20.3.18 or later for v20 users, 21.2.4 or later for v21 users, or 22.0.0-next.3 or later for preview branch users. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours: Identify all applications using Angular and determine which leverage i18n attributes on href, src, action, or similar security-sensitive attributes. …
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External POC / Exploit Code
Leaving vuln.today
EUVD-2026-12140
GHSA-g93w-mfhg-p222