W3 Total Cache <= 2.10.5 - Unauthenticated Stored Cross-Site Scripting via LazyLoad Background Mutator
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Cross-site scripting
- Confidentiality · integrity · availability
- Low · Low · None
- Fix status
- No fix listed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-79.
Summary
The W3 Total Cache plugin for WordPress is vulnerable to Stored Cross-Site Scripting via Comment Content via LazyLoad Background Mutator in all versions up to, and including, 2.10.5 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. This requires the "Lazy Load Images" feature with "Process background images" to be enabled, and the malicious comment to be approved by a moderator before execution is triggered.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
No fixed version listed by the sources yet.
Timeline
- 2026-10-02 Threatist record created from CVE-2026-78438
- 2026-10-03 Alias added: GHSA-6p3q-4gcg-xv4v
References
Other 8
- https://www.wordfence.com/threat-intel/vulnerabilities/id/5580ad05-af50-4899-9cbf-39ad8000eb6a?source=cve
- https://plugins.trac.wordpress.org/browser/w3-total-cache/tags/2.10.5/UserExperience_LazyLoad_Mutator.php#L293
- https://plugins.trac.wordpress.org/browser/w3-total-cache/tags/2.10.5/UserExperience_LazyLoad_Mutator.php#L255
- https://plugins.trac.wordpress.org/browser/w3-total-cache/tags/2.10.5/UserExperience_LazyLoad_Mutator.php#L91
- https://plugins.trac.wordpress.org/browser/w3-total-cache/tags/2.10.5/UserExperience_LazyLoad_Plugin.php#L87
- https://plugins.trac.wordpress.org/changeset?reponame=&new=3680101%40w3-total-cache%2Ftags%2F2.10.6&old=3653442%40w3-total-cache%2Ftags%2F2.10.5
- https://plugins.trac.wordpress.org/changeset?old_path=%2Fw3-total-cache/tags/2.10.5&new_path=%2Fw3-total-cache/tags/2.10.6
- https://plugins.trac.wordpress.org/changeset/3680101/w3-total-cache/tags/2.10.6/UserExperience_LazyLoad_Mutator.php
More BoldGrid vulnerabilities
- TI-2013-01782 WordPress W3 Total Cache Plugin 0.9.2.8 has a Remote PHP Code Execution Vulnerability CVSS 3.1CRITICAL 9.8
- TI-2019-04758 pub/sns.php in the W3 Total Cache plugin before 0.9.4 for WordPress allows remote… CVSS 3.1HIGH 7.5
- TI-2025-39670 WordPress Client Invoicing by Sprout Invoices plugin <= 20.8.7 - PHP Object Injection vulnerability CVSS 3.1CRITICAL 9.8
- TI-2026-04390 W3 Total Cache <= 2.9.3 - Unauthenticated Security Token Exposure via User-Agent Header CVSS 3.1HIGH 7.5
- TI-2026-08154 W3 Total Cache <= 2.9.4 - Unauthenticated Arbitrary File Read via 'f_array[]' Parameter CVSS 3.1HIGH 7.5
- TI-2024-11141 W3 Total Cache <= 2.8.1 Information Exposure via Log Files CVSS 3.1HIGH 7.5
Sources
- CVE-2026-78438 · CVE Program
- CVE-2026-78438 · NVD
- FIRST EPSS
- GHSA-6p3q-4gcg-xv4v · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences