Cross-Site Scripting (XSS) in Angular Language Service (CVE-2026-49241)
Summary
Cross-site scripting in Angular Language Service (CVE-2026-49241). Successful exploitation can lead to full system takeover. Mitigation: upgrade to 21.2.4 or later.
Original description
The description as published by the source.
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.
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-49241 has been found in Angular Language Service.
Successful exploitation can lead to full system takeover. CVSS score: 8.8/10.
What to do: upgrade Angular Language Service to 21.2.4 or later.
If unsure, ask your IT team or search "Angular Language Service CVE-2026-49241" on the vendor's site.
CVE-2026-49241 (Angular Language Service) — CWE-79 / CVSS v3 8.8
Attack vector: remote (network-reachable) / unauthenticated
Patched: 21.2.4 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
Cross-site scripting (XSS) (CWE-79) exists in Angular Language Service.
Check the vendor advisory for the affected versions of Angular Language Service.
Severity: High (CVSS 8.8/10). Successful exploitation can lead to full system takeover.
Update to 21.2.4.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
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1Identify exposure identify
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで Angular Language Service を使っているサービスとバージョンを洗い出す。
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2Apply patch patch
Upgrade Angular Language Service to 21.2.4ステージング環境で 21.2.4 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
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3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Ubuntu UBUNTU-CVE-2026-49241 angular.js
References
- advisory github.com
- advisory github.com
- advisory nvd.nist.gov
- patch github.com
- patch github.com