Angular i18n vulnerable to Cross-Site Scripting (XSS)

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Angular is a development platform for building mobile and desktop web applications using TypeScript/JavaScript and other languages. Versions prior to 21.2.0, 21.1.16, 20.3.17, and 19.2.19 have a cross-Site scripting vulnerability in the Angular internationalization (i18n) pipeline. In ICU messages (International Components for Unicode), HTML from translated content was not properly sanitized and could execute arbitrary JavaScript. Angular i18n typically involves three steps, extracting all messages from an application in the source language, sending the messages to be translated, and then merging their translations back into the final source code. Translations are frequently handled by contracts with specific partner companies, and involve sending the source messages to a separate contractor before receiving final translations for display to the end user. If the returned translations have malicious content, it could be rendered into the application and execute arbitrary JavaScript. When successfully exploited, this vulnerability allows for execution of attacker controlled JavaScript in the application origin. Depending on the nature of the application being exploited this could lead to credential exfiltration and/or page vandalism. Several preconditions apply to the attack. The attacker must compromise the translation file (xliff, xtb, etc.). Unlike most XSS vulnerabilities, this issue is not exploitable by arbitrary users. An attacker must first compromise an application's translation file before they can escalate privileges into the Angular application client. The victim application must use Angular i18n, use one or more ICU messages, render an ICU message, and not defend against XSS via a safe content security policy. Versions 21.2.0, 21.1.6, 20.3.17, and 19.2.19 patch the issue. Until the patch is applied, developers should consider reviewing and verifying translated content received from untrusted third parties before incorporating it in an Angular application, enabling strict CSP controls to block unauthorized JavaScript from executing on the page, and enabling Trusted Types to enforce proper HTML sanitization.

Source published

26 Feb 2026 02:03:43 UTC

Source modified

15 Jul 2026 01:12:09 UTC

Saved here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

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Source: cve-program · CVE Program Terms of Use. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

CVSS 4.0 · 7.6 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

Angular is a development platform for building mobile and desktop web applications using TypeScript/JavaScript and other languages. Versions prior to 21.2.0, 21.1.16, 20.3.17, and 19.2.19 have a cross-Site scripting vulnerability in the Angular internationalization (i18n) pipeline. In ICU messages (International Components for Unicode), HTML from translated content was not properly sanitized and could execute arbitrary JavaScript. Angular i18n typically involves three steps, extracting all messages from an application in the source language, sending the messages to be translated, and then merging their translations back into the final source code. Translations are frequently handled by contracts with specific partner companies, and involve sending the source messages to a separate contractor before receiving final translations for display to the end user. If the returned translations have malicious content, it could be rendered into the application and execute arbitrary JavaScript. When successfully exploited, this vulnerability allows for execution of attacker controlled JavaScript in the application origin. Depending on the nature of the application being exploited this could lead to credential exfiltration and/or page vandalism. Several preconditions apply to the attack. The attacker must compromise the translation file (xliff, xtb, etc.). Unlike most XSS vulnerabilities, this issue is not exploitable by arbitrary users. An attacker must first compromise an application's translation file before they can escalate privileges into the Angular application client. The victim application must use Angular i18n, use one or more ICU messages, render an ICU message, and not defend against XSS via a safe content security policy. Versions 21.2.0, 21.1.6, 20.3.17, and 19.2.19 patch the issue. Until the patch is applied, developers should consider reviewing and verifying translated content received from untrusted third parties before incorporating it in an Angular application, enabling strict CSP controls to block unauthorized JavaScript from executing on the page, and enabling Trusted Types to enforce proper HTML sanitization.

Source published

Feb 26, 2026, 2:03:43 AM (timezone not stated)

Source modified

Jul 15, 2026, 1:12:09 AM (timezone not stated)

Saved here

13 Nov 2026 09:57:31 UTC

Source terms

ENISA EUVD · source terms and attribution apply

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EUVD CVSS 4.0 · 7.6 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

Angular is a development platform for building mobile and desktop web applications using TypeScript/JavaScript and other languages. Versions prior to 21.2.0, 21.1.16, 20.3.17, and 19.2.19 have a cross-Site scripting vulnerability in the Angular internationalization (i18n) pipeline. In ICU messages (International Components for Unicode), HTML from translated content was not properly sanitized and could execute arbitrary JavaScript. Angular i18n typically involves three steps, extracting all messages from an application in the source language, sending the messages to be translated, and then merging their translations back into the final source code. Translations are frequently handled by contracts with specific partner companies, and involve sending the source messages to a separate contractor before receiving final translations for display to the end user. If the returned translations have malicious content, it could be rendered into the application and execute arbitrary JavaScript. When successfully exploited, this vulnerability allows for execution of attacker controlled JavaScript in the application origin. Depending on the nature of the application being exploited this could lead to credential exfiltration and/or page vandalism. Several preconditions apply to the attack. The attacker must compromise the translation file (xliff, xtb, etc.). Unlike most XSS vulnerabilities, this issue is not exploitable by arbitrary users. An attacker must first compromise an application's translation file before they can escalate privileges into the Angular application client. The victim application must use Angular i18n, use one or more ICU messages, render an ICU message, and not defend against XSS via a safe content security policy. Versions 21.2.0, 21.1.6, 20.3.17, and 19.2.19 patch the issue. Until the patch is applied, developers should consider reviewing and verifying translated content received from untrusted third parties before incorporating it in an Angular application, enabling strict CSP controls to block unauthorized JavaScript from executing on the page, and enabling Trusted Types to enforce proper HTML sanitization.

Source published

26 Feb 2026 02:16:24 UTC

Source modified

15 Jul 2026 02:19:13 UTC

Saved here

25 Oct 2026 06:17:33 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

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CVSS 4.0 · [email protected] · Secondary · 7.6 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/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 · 6.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

CVSS 3.1 · 0b0ca135-0b70-47e7-9f44-1890c2a1c46c · Secondary · 7.1 CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:L

A [Cross-site Scripting (XSS)](https://developer.mozilla.org/en-US/docs/Web/Security/Attacks/XSS) vulnerability has been identified in the Angular internationalization (i18n) pipeline. In ICU messages (International Components for Unicode), HTML from translated content was not properly sanitized and could execute arbitrary JavaScript. Angular i18n typically involves three steps, extracting all messages from an application in the source language, sending the messages to be translated, and then merging their translations back into the final source code. Translations are frequently handled by contracts with specific partner companies, and involve sending the source messages to a separate contractor before receiving final translations for display to the end user. If the returned translations have malicious content, it could be rendered into the application and execute arbitrary JavaScript. ### Impact When successfully exploited, this vulnerability allows for execution of attacker controlled JavaScript in the application origin. Depending on the nature of the application being exploited this could lead to: - **Credential Exfiltration**: Stealing sensitive user data stored in page memory, LocalStorage, IndexedDB, or cookies available to JS and sending them to an attacker controlled server. - **Page Vandalism:** Mutating the page to read or act differently than intended by the developer. ### Attach Preconditions - **The attacker must compromise the translation file (xliff, xtb, etc.).** - Unlike most XSS vulnerabilities, this one is not exploitable by arbitrary users. An attacker must first compromise an application's translation file before they can escalate privileges into the Angular application client. - The victim application must use Angular i18n. - The victim application must use one or more ICU messages. - The victim application must render an ICU message. - The victim application must not defend against XSS via a safe [Content-Security Policy (CSP)](https://developer.mozilla.org/en-US/docs/Web/HTTP/Guides/CSP) or [Trusted Types](https://developer.mozilla.org/en-US/docs/Web/API/Trusted_Types_API). ### Patches - 21.2.0 - 21.1.6 - 20.3.17 - 19.2.19 ### Workarounds Until the patch is applied, developers should consider: - **Reviewing and verifying translated content** received from untrusted third parties before incorporating it in an Angular application. - **Enabling strict CSP controls** to block unauthorized JavaScript from executing on the page. - [**Enabling Trusted Types**](https://angular.dev/best-practices/security#enforcing-trusted-types) to enforce proper HTML sanitization. ### References - [Fix](https://github.com/angular/angular/pull/67183)

Source published

27 Feb 2026 18:33:16 UTC

Source modified

10 Sep 2026 03:50:59 UTC

Saved here

24 Oct 2026 13:17:17 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

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Source: osv · GitHub Advisory Database · CC-BY-4.0. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

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

Publisher rating · HIGH