Quick answers
- Is CVE-2026-78438 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-78438 being exploited in the wild.
- How severe is CVE-2026-78438?
- High severity, with a CVSS score of 7.2, published 5 September 2026.
- Which products and versions are affected?
- W3 Edge W3 Total Cache up to and including 2.10.5.
- Is there a fix for CVE-2026-78438?
- No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
- How is CVE-2026-78438 attacked?
- It is attacked over the network, in a software library.
- Am I affected by CVE-2026-78438?
- Check whether anything you run is named in the advisory. 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.
Technical details
The vulnerability is a stored cross-site scripting (XSS) flaw in the LazyLoad Background Mutator component that fails to properly sanitize and escape user-supplied comment content. When the "Lazy Load Images" feature with "Process background images" is enabled, an unauthenticated attacker can inject arbitrary web scripts via comment fields. The injected script persists in the database and executes in the context of any user viewing the page. Exploitation requires the malicious comment to be approved by a moderator, and the feature to be enabled. The vulnerability affects W3 Total Cache versions up to and including 2.10.5.
Affected products
- W3 Edge W3 Total Cache up to and including 2.10.5
Timeline
- 2026-09-05: disclosed