# locize Client SDK: Cross-origin DOM XSS & Handler Hijack Through Missing e.origin Validation in InContext Editor

Advisory record · `GHSA-w937-fg2h-xhq2`

- **Identifiers:** `GHSA-w937-fg2h-xhq2` · `CVE-2026-41886`
- **State:** Confirmed
- **Severity:** CVSS 7.5 High
- **Critical:** No
- **Weakness (CWE):** [CWE-79](https://cwe.mitre.org/data/definitions/79.html) · [CWE-346](https://cwe.mitre.org/data/definitions/346.html)
- **Tags:** [Cross-site scripting (XSS)](https://agentprime.io/advisories/tag/xss.md) · [CWE-346](https://agentprime.io/advisories/tag/cwe-346.md)
- **Published:** 22 Apr 2026
- **Updated:** 13 May 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 22 Apr 2026, 20:32 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `locize` (npm): affected `<4.0.21`; fixed in `4.0.21`

## Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

## Severity and exploitation

- 7.5 High, CVSS 3.1: `CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:H/A:L`, from CNA (GitHub_M)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0010, the 1st percentile, on 10 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

This record came from the full history of the GitHub Advisory Database, published 22 Apr 2026. New records show when each source confirmed them.

## Sources

- [GitHub Advisory Database: GHSA-w937-fg2h-xhq2](https://github.com/advisories/GHSA-w937-fg2h-xhq2)
- [OSV: GHSA-w937-fg2h-xhq2](https://osv.dev/vulnerability/GHSA-w937-fg2h-xhq2)
- <https://github.com/locize/locize/security/advisories/GHSA-w937-fg2h-xhq2>
- <https://nvd.nist.gov/vuln/detail/CVE-2026-41886>
- <https://github.com/locize/locize/commit/d006b75fadb8e8ab77b023e462850fc6e9170735>
- <https://developer.mozilla.org/en-US/docs/Web/API/Window/postMessage#security_concerns>
- <https://github.com/locize/locize>
- <https://github.com/locize/locize/releases/tag/v4.0.21>

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.

## Check whether this affects you

A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-w937-fg2h-xhq2>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

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The web page: <https://agentprime.io/advisories/GHSA-w937-fg2h-xhq2/>. Everything for agents: <https://agentprime.io/llms.txt>.