Packages / @angular/core / Security
Angular i18n vulnerable to Cross-Site Scripting
Affected releases · @angular/core
- 21.x21.0.0 – 21.1.5Fixed in 21.1.6
- 20.x20.0.0 – 20.3.16Fixed in 20.3.17
- 19.x19.0.0 – 19.2.18Fixed in 19.2.19
- 18.x and older2.0.0 – 18.2.14No fix, no longer updated
On 21.x, the newest line:
npm install @angular/core@21.1.6Not affected
22.0.0 – 22.2.3
22 releases, latest
Affected
21.0.0 – 21.1.5
16 releases
Fixed
21.1.6 – 21.2.25
27 releases
Affected
20.0.0 – 20.3.16
38 releases
Fixed
20.3.17 – 20.3.34
18 releases
Affected
19.0.0 – 19.2.18
36 releases
Fixed
19.2.19 – 19.2.25
7 releases
Affected
18.0.0 – 18.2.14
29 releases
Affected
17.0.0 – 17.3.12
32 releases
Affected
16.0.0 – 16.2.12
30 releases
Affected
15.0.0 – 15.2.10
22 releases
Affected
14.0.0 – 14.3.0
26 releases
Affected
13.0.0 – 13.4.0
30 releases
Affected
12.0.0 – 12.2.17
30 releases
Affected
11.0.0 – 11.2.14
28 releases
Affected
10.0.0 – 10.2.5
28 releases
Affected
9.0.0 – 9.1.13
22 releases
Affected
8.0.0 – 8.2.14
23 releases
Affected
7.0.0 – 7.2.16
27 releases
Affected
6.0.0 – 6.1.10
20 releases
Affected
5.0.0 – 5.2.11
22 releases
Affected
4.0.0 – 4.4.7
30 releases
Affected
2.0.0 – 2.4.10
24 releases
Is your project affected?
Paste your package.json, or type the range you declare for @angular/core. It is read in your browser and sent nowhere.
What happens
A Cross-site Scripting (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) or Trusted Types.
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 to enforce proper HTML sanitization.
References