{"id":"CVE-2026-50555","aliases":["GHSA-hqr9-c56f-3x7f"],"title":"@angular/platform-server: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')","summary":"@angular/platform-server: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')","severity":"high","cwe":["CWE-79"],"vendor":"angular","product":"@angular/platform-server","ecosystem":"npm","affected":["@angular/platform-server >= 22.0.0-next.0, < 22.0.0-rc.2","@angular/platform-server >= 21.0.0-next.0, < 21.2.16","@angular/platform-server >= 20.0.0-next.0, < 20.3.24","@angular/platform-server >= 19.0.0-next.0, < 19.2.25","@angular/platform-server <= 18.2.14"],"patched":["@angular/platform-server 22.0.0-rc.2","@angular/platform-server 21.2.16","@angular/platform-server 20.3.24","@angular/platform-server 19.2.25"],"published":"2026-06-15","updated":"2026-06-15","source":"GHSA","sourceUrl":"https://github.com/advisories/GHSA-hqr9-c56f-3x7f","references":[{"url":"https://github.com/angular/angular/security/advisories/GHSA-hqr9-c56f-3x7f"},{"url":"https://github.com/angular/domino/pull/29"},{"url":"https://github.com/advisories/GHSA-hqr9-c56f-3x7f"}],"tags":["ghsa","npm"],"epss":0.00267,"epssPercentile":0.19052,"ingestedAt":"2026-07-07T15:41:58.930Z","slug":"CVE-2026-50555","body":"## Overview\n\nA 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>`).\n\n`domino` supports escaping raw-text elements during serialization to prevent closing-tag breakout. However, a **Unicode index alignment bug** existed in this escaping logic.\n\nIn 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.\n\nThis misalignment caused `domino` to fail to replace or escape the closing tag, leaving it raw and unescaped in the output HTML.\n\nAn 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).\n\n### Impact\n\nThis vulnerability allows an attacker to perform same-origin Cross-Site Scripting (XSS) attacks against any user visiting an SSR-rendered page that binds user-controlled data inside raw-text elements. This can lead to session hijacking, credentials theft, unauthorized actions on behalf of users, and defacement.\n\n### Patched Versions\n\n- 22.0.0-rc.2\n- 21.2.16\n- 20.3.24\n- 19.2.25\n\n### Workarounds\n\nIf you cannot immediately update your dependencies, you can:\n\n- Avoid binding user-controlled values inside `<iframe>` or other raw-text elements.\n- Sanitize any user input placed inside raw-text elements to explicitly strip closing tags before passing it to the template.\n\n## Affected packages\n\n- `@angular/platform-server >= 22.0.0-next.0, < 22.0.0-rc.2`\n- `@angular/platform-server >= 21.0.0-next.0, < 21.2.16`\n- `@angular/platform-server >= 20.0.0-next.0, < 20.3.24`\n- `@angular/platform-server >= 19.0.0-next.0, < 19.2.25`\n- `@angular/platform-server <= 18.2.14`\n\n## Remediation\n\nUpgrade to a patched release:\n\n- `@angular/platform-server 22.0.0-rc.2`\n- `@angular/platform-server 21.2.16`\n- `@angular/platform-server 20.3.24`\n- `@angular/platform-server 19.2.25`","depth":"twilight","depthScore":41,"depthScoreParts":{"impact":41.3,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}