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Vulnerabilities

Vulnerability · CVE-2026-35055

XenForo before 2.3.9 and before 2.2.18 is vulnerable to cross-site scripting (XSS) related to lightbox usage in posts.

Published Apr 1, 2026 · catalog updated Jun 17, 2026 · XenForo before 2.3.9 and

Check if you run it

No confirmed exploitation is on record for CVE-2026-35055. EPSS is 0.27%. Act only if a listed version of XenForo before 2.3.9 and is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (XenForo before 2.3.9 and).
  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Medium5.1
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.27%
Remediation
Advisory link
Affected products
cpe xenforo/xenforo

XenForo before 2.3.9 and before 2.2.18 is vulnerable to cross-site scripting (XSS) related to lightbox usage in posts. An attacker can inject malicious scripts that execute when users interact with post content displayed in the lightbox.

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.

  • cpe xenforo/xenforoversion unspecified

How to fix CVE-2026-35055

What to do

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

Should you patch?

No confirmed exploitation is on record for CVE-2026-35055. EPSS is 0.27%. Act only if a listed version of XenForo before 2.3.9 and is installed.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-79: Cross-site Scripting (XSS). EPSS 0.27%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

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. Apr 1, 2026 · NIST NVD

    Detected

    XenForo before 2.3.9 and before 2.2.18 is vulnerable to cross-site scripting (XSS) related to lightbox usage in posts. An attacker can inject malicious scripts that execute when users interact with post content displayed in the lightbox.

  2. Jun 17, 2026 · NIST NVD

    Updated

    XenForo before 2.3.9 and before 2.2.18 is vulnerable to cross-site scripting (XSS) related to lightbox usage in posts. An attacker can inject malicious scripts that execute when users interact with post content displayed in the lightbox.

Sources

  • CVE.orgVulnerability recordCVE-2026-35055

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-35055

    30-day exploitation probability 0.3%

    first.org
  • NIST NVDVulnerability recordCVE-2026-35055

    XenForo before 2.3.9 and before 2.2.18 is vulnerable to cross-site scripting (XSS) related to lightbox usage in posts. An attacker can inject malicious scripts that execute when users interact with post content displayed in the lightbox.

    nvd.nist.gov

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.