CVE-2026-27970 Angular i18n vulnerable to Cross-Site Scripting (XSS)
Attackers can execute arbitrary JavaScript in Angular applications by compromising translation files containing malicious ICU messages, leading to credential theft or page vandalism.
- 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
- Fix
- Available
What is CVE-2026-27970?
CVE-2026-27970 is a high-severity cross-site scripting vulnerability in angular, published on 26 Feb 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
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.
Weakness: CWE-79
Which versions are affected by CVE-2026-27970?
10 open source packages ship an affected version, including @angular/core. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
@angular/core npm | All versions to 18.2.14 | None |
@angular/core npm | All versions to 18.2.14 | None |
@angular/core npm | From 19.0.0-next.0 | 19.2.19 |
@angular/core npm | From 19.0.0-next.0 | 19.2.19 |
@angular/core npm | From 20.0.0-next.0 | 20.3.17 |
@angular/core npm | From 20.0.0-next.0 | 20.3.17 |
4 more packages
@angular/core npm | From 21.0.0-next.0 | 21.1.6 |
@angular/core npm | From 21.0.0-next.0 | 21.1.6 |
@angular/core npm | From 21.2.0-next.0 | 21.2.0 |
@angular/core npm | From 21.2.0-next.0 | 21.2.0 |
Products include Angular Angular.
How do I fix CVE-2026-27970?
Upgrade @angular/core to a fixed version for your release line: 19.2.19, 20.3.17, 21.1.6 or 21.2.0.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-27970 being exploited?
There is no known exploitation of CVE-2026-27970 in the wild and no public exploit code.
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- CVE-2026-46417 Angular: SSRF via Hostname Hijacking in @angular/platform-server
- CVE-2026-50168 Angular: URL Parser Differential in @angular/platform-server leading to SSRF Allowlist Bypass
- CVE-2026-54266 Angular: Weak 32-Bit Cache Key Hashing in `HttpTransferCache` Leading to Cross-Request Data Leakage and State Poisoning
- CVE-2026-41423 Angular: SSRF via protocol-relative and backslash URLs in Angular Platform-Server
Sources
Also known as CLSA-2026-1775176191, CLSA-2026-1775176192, CLSA-2026-1775781181, CLSA-2026-1776040411, CLSA-2026-1776040414, CLSA-2026-1776040417 and 188 more.