Angular: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') in @angular/platform-server

Description

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, 21.2.16, 20.3.24, and 19.2.25, a Cross-Site Scripting (XSS) vulnerability exists in @angular/platform-server's DOM emulation dependency (domino) when serializing the content of raw-text elements (such as <script>, <style>, and <iframe>). domino supports escaping raw-text elements during serialization to prevent closing-tag breakout. However, a Unicode index alignment bug existed in this escaping logic. In JavaScript, string lengths and character indices are calculated based on UTF-16 code units (where astral characters—such as emojis—occupy 2 code units / 4 bytes). If the bound dynamic text contained astral Unicode characters before the closing tag (e.g. </script>, </style>, or </iframe>), the index offset calculation in domino's replacement logic shifted. This misalignment caused domino to fail to replace or escape the closing tag, leaving it raw and unescaped in the output HTML. An attacker who controls the dynamic text can supply a payload containing both an astral Unicode character and a closing tag (e.g., 😀</iframe><script>alert(1)</script>). When serialized on the server during SSR, the browser parses the unescaped closing tag, exits the raw-text context early, and executes the subsequent <script> block, leading to same-origin Cross-Site Scripting (XSS). This vulnerability is fixed in 22.0.0-rc.2, 21.2.16, 20.3.24, and 19.2.25.

Timeline

Scores

EPSS (exploitation in 30 days)

0.27% · top 81% of all CVEs (7 Nov 2026)

CISA SSVC

Exploitation: none · Automatable: no · Technical impact: total

The list uses the assigner's score when there is one, then CISA's, then NVD's: High 8.6.

Weakness

• CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (opens in a new tab)All about CWE-79 and its CVEs

Affected products

• angular · angular

  • affected >= 22.0.0-next.0, < 22.0.0-rc.2
  • affected >= 21.0.0-next.0, < 21.2.16
  • affected >= 20.0.0-next.0, < 20.3.24
  • affected >= 19.0.0-next.0, < 19.2.25
  • affected <= 18.2.14

Affected packages

From reviewed advisories of the GitHub Advisory Database.

• npm@angular/platform-serverGHSA-hqr9-c56f-3x7f (opens in a new tab)

References (2)

• https://github.com/angular/angular/security/advisories/GHSA-hqr9-c56f-3x7f (opens in a new tab)x_refsource_CONFIRM
• https://github.com/angular/domino/pull/29 (opens in a new tab)x_refsource_MISC

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisory GHSA-hqr9-c56f-3x7f (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2026-50555](https://trackcve.app/badge/CVE-2026-50555.svg)](https://trackcve.app/cve/CVE-2026-50555)

Record last updated 22 Jun 2026, 17:58 UTC.