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Vulnerabilities

Vulnerability · CVE-2026-18109

BoldGrid w3_total_cache Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Published Aug 14, 2026 · catalog updated Aug 14, 2026 · BoldGrid

Patch now

CVE-2026-18109 is in the CISA known-exploited catalog. Confirm BoldGrid against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Severity
Unknown—
Known exploitation
CISA KEV and VulnCheck KEV
EPSS
0.43%
Remediation
Remediation guidance
Affected products
stated w3_total_cache · vendor BoldGrid w3_total_cache

The W3 Total Cache plugin for WordPress is vulnerable to Stored Cross-Site Scripting via Comment Author Name in all versions up to, and including, 2.10.3 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 vulnerability is only exploitable when the Lazy Load Images feature of W3 Total Cache is enabled, as the unsafe re-emission occurs exclusively within the LazyLoad mutator's img tag rewriting step.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • stated w3_total_cache<= 2.10.3
  • vendor BoldGrid w3_total_cacheversion unspecified

How to fix CVE-2026-18109

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

CVE-2026-18109 is in the CISA known-exploited catalog. Confirm BoldGrid against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Which versions are affected?

Compare what you have installed with <= 2.10.3. Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.

What should an analyst verify?

No weakness class is stored. EPSS 0.43%. The CISA KEV listing is the exploitation evidence. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Technology hubs

WordPress security

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Aug 14, 2026 · VulnCheck KEV

    Detected

    The W3 Total Cache plugin for WordPress is vulnerable to Stored Cross-Site Scripting via Comment Author Name in all versions up to, and including, 2.10.3 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 vulnerability is only expl

  2. Aug 14, 2026 · CISA KEV

    Known exploited

    Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.

Sources

  • CVE.orgVulnerability recordCVE-2026-18109

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-18109

    30-day exploitation probability 0.4%

    first.org
  • VulnCheck KEVConfirmed exploitationCVE-2026-18109

    The W3 Total Cache plugin for WordPress is vulnerable to Stored Cross-Site Scripting via Comment Author Name in all versions up to, and including, 2.10.3 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arb

    vulncheck.com

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.