# CVE-2026-120845: WPMU DEV Smush Image Compression stored cross-site scripting

Source: https://junglewise.ai/threats/cve-2026-120845-improper-neutralization-of-input-during-web-page-generation  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-11-06. Updated: 2026-11-06  
License: CC BY 4.0 with a link back

CVE-2026-120845 · Severity: medium · CVSS 6.5 · Published 2026-11-06

WPMU DEV Smush is a WordPress plugin that compresses and optimizes images on websites. A stored cross-site scripting vulnerability in versions up to 4.3.5 allows attackers with contributor or higher privileges to inject malicious scripts that execute in the browsers of site visitors, potentially stealing data or hijacking accounts.

Vendors: [WPMU DEV](https://junglewise.ai/threats/vendors/wpmu-dev).

## Quick answers

**Is CVE-2026-120845 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-120845 being exploited in the wild.

**How severe is CVE-2026-120845?** Medium severity, with a CVSS score of 6.5, published 6 November 2026.

**Which products and versions are affected?** WPMU DEV Smush Image Compression and Optimization through 4.3.5.

**Is there a fix for CVE-2026-120845?** Yes: fixed in 4.3.6. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-120845 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-120845?** Check whether you run WPMU DEV Smush Image Compression and Optimization at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in 4.3.6

## Technical details

The plugin improperly neutralizes user input during web page generation, allowing authenticated attackers (with contributor role or above) to inject persistent XSS payloads. The malicious scripts are stored and executed in visitors' browsers when pages are rendered. This stored XSS can lead to session hijacking, credential theft, and malware distribution.

## Affected products

- WPMU DEV Smush Image Compression and Optimization through 4.3.5

## Timeline

- 2026-10-23: disclosed: Reported to Patchstack
- 2026-11-06: advisory: Published by Patchstack and CVE-2026-120845 assigned
- 2026-11-06: patched: Version 4.3.6 released

## References

- [https://wordpress.org/plugins](https://wordpress.org/plugins)
- [https://patchstack.com/database/wordpress/plugin/wp-smushit/vulnerability/wordpress-smush-image-compression-and-optimization-plugin-4-3-5-cross-site-scripting-xss-vulnerability?_s_id=cve](https://patchstack.com/database/wordpress/plugin/wp-smushit/vulnerability/wordpress-smush-image-compression-and-optimization-plugin-4-3-5-cross-site-scripting-xss-vulnerability?_s_id=cve)

## Related threats

- [Smush Image Compression and Optimization unauthenticated denial of service](https://junglewise.ai/threats/cve-2026-81285-smush-image-compression-and-optimization-unauthenticated-denial)