CVE-2026-54268: Angular Uncontrolled Resource Consumption (CVSS 8.2)

Angular is a development platform for building mobile and desktop web applications using TypeScript/JavaScript and other languages. Prior to 20.3.30, 21.2.22, and 22.1.4, Angular Server-Side Rendering in @angular/platform-server processes user-controlled resource or request URLs through HttpClient after application code validates them with WHATWG URL parsing. The resolveUrl and parseUrl utilities called String.prototype.trim(), which removed leading Unicode whitespace such as U+00A0 or U+FEFF after the input passed a same-origin check, converting a relative path into a protocol-relative attacker-controlled URL. In affected applications that attach sensitive server-side credentials such as Authorization headers to approved requests, relativeUrlsTransformerInterceptorFn then dispatched the request to the attacker-controlled origin, causing SSRF and credential disclosure. This issue is fixed in versions 20.3.30, 21.2.22, and 22.1.4.

Angular is a development platform for building mobile and desktop web applications using TypeScript/JavaScript and other languages. Prior to 22.0.0-rc.2, 21.2.15, 20.3.22, and 19.2.23, a vulnerability was discovered in @angular/common when Server-Side Rendering (SSR) and hydration are enabled. The HttpTransferCache utility optimizes hydration by caching outgoing HTTP requests performed during SSR and transferring the cached state to the client-side application via TransferState. However, the caching mechanism fails to inspect the withCredentials flag or the Cookie header of outgoing requests. As a result, credentialed, user-specific responses may be cached by default in the shared TransferState payload. When these responses are serialized into the HTML, any caching layer (such as a CDN, reverse proxy, or shared server cache) that caches the SSR-rendered HTML page could inadvertently cache and leak one user's private data to other users, leading to a high-severity information disclosure vulnerability. This vulnerability is fixed in 22.0.0-rc.2, 21.2.15, 20.3.22, and 19.2.23.

Angular is a development platform for building mobile and desktop web applications using TypeScript/JavaScript and other languages. Prior to 22.0.0-rc.2, 21.2.15, 20.3.22, and 19.2.23, an issue in the @angular/platform-server package allows remote attackers to bypass host allowlist constraints and direct server-side outgoing requests to arbitrary external endpoints. This occurs due to a parser differential between the strict WHATWG URL parser used for allowlist validation and the lenient Domino URL parser used to initialize the server emulated DOM. When a server-side request contains a malformed URL with a double port structure (e.g., http://evil.com:80:80/path), Node's strict URL.canParse(url) logic returns false and skips host check validation entirely. However, the same malformed URL is later accepted and parsed leniently by Domino's internal parser, which resolves the origin to http://evil.com:80. The Angular SSR HTTP request interceptor (relativeUrlsTransformerInterceptorFn) then resolves all relative backend HTTP requests against this adopted origin, executing the SSRF attack. This vulnerability is fixed in 22.0.0-rc.2, 21.2.15, 20.3.22, and 19.2.23.

The Angular Language Service VS Code Extension provides a rich editing experience for Angular templates. the client-side Angular Language Service VS Code extension configures the tooltip Markdown renderer with the isTrusted: true option (located in client/src/client.ts). This setting instructs VS Code to trust all rendered content it receives, which enables active elements such as command: URIs. However, the background Angular Language Server process fails to escape or sanitize brackets, raw links, and control characters from JSDoc strings before forwarding the hover Markdown content (located in server/src/handlers/hover.ts and server/src/text_render.ts). An attacker can leverage this behavior by crafting a project TypeScript or JavaScript file (or a third-party npm package dependency) containing a malicious JSDoc tooltip with an embedded active command link. When a developer hovers over the target symbol to render the tooltip and clicks the malicious link, the IDE executes the command sequence directly on the developer's host machine. Prior to 21.2.4, This vulnerability is fixed in 21.2.4.

The Angular Language Service VS Code Extension provides a rich editing experience for Angular templates. Prior to 21.2.4, the client-side Angular Language Service VS Code extension reads the custom TypeScript SDK paths typescript.tsdk and js/ts.tsdk.path directly from workspace configurations (.vscode/settings.json) without verifying VS Code Workspace Trust state or asking for user consent (located in client/src/client.ts). The client-side extension then passes the parsed settings path as a command-line argument (--tsdk) to the background Node.js language server process. During server initialization, the background language server resolves and dynamically imports (via standard Node.js require()) the module library tsserverlibrary.js relative to the workspace-specified custom directory path. An attacker can exploit this behavior by committing a repository containing a local malicious tsserverlibrary.js script inside a custom folder, and a crafted .vscode/settings.json file pointing to that folder. When a developer opens the repository folder in VS Code, the extension automatically attempts to initialize and load the server, which dynamically resolves, loads, and executes the malicious script silently in the background. This vulnerability is fixed in 21.2.4.

Angular is a development platform for building mobile and desktop web applications using TypeScript/JavaScript and other languages. Prior to 22.0.0-next.3, 21.2.4, 20.3.18, and 19.2.20, 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. This vulnerability is fixed in 22.0.0-next.3, 21.2.4, 20.3.18, and 19.2.20.