CVE-2026-18978 json
LiteSpeed Cache <= 7.8.1 - Unauthenticated Stored Cross-Site Scripting via Comment Content
published 2026-08-28 2 mo ago modified 2026-08-28 2 mo ago also EUVD-2026-67404
- cvss
- 7.2
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.4%
- EPSS 0.4% chance of exploitation in 30 days, percentile 39%
- public exploits
- 0
- none known
Summary
The LiteSpeed Cache plugin for WordPress is vulnerable to Stored Cross-Site Scripting via Comment Content in all versions up to, and including, 7.8.1 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. A comment payload crafted exclusively from decimal numeric character references (e.g. ", <, >) placed inside an allowed element such as <code> bypasses WordPress's wp_kses sanitization, as kses does not treat a data-settings="..." substring within text content as an HTML attribute, allowing the malicious payload to reach the vulnerable function. For this to be exploitable, the site must allow users with previously approved comments to write new comments, and the require_name_email setting must be disabled.
CISA SSVC
- Exploitation
- none
- Automatable
- yes
- Technical impact
- partial
- Assessed
- 2 mo ago
Exploit prediction
0.45% chance of exploitation in the next 30 days, higher than 39% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 7.2 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N |
Affected products
- litespeedtech LiteSpeed Cache
Classification
- Weakness
-
- CWE-79 Improper Neutralization of Input During Web Page Generation
- Technology feeds
References
- wordfence.com /threat-intel/vulnerabilities/id/0b045f3d-8412-4e35-b369-2b485639274d?source=cve
- plugins.trac.wordpress.org /browser/litespeed-cache/trunk/src/media.cls.php#L1405
- plugins.trac.wordpress.org /browser/litespeed-cache/trunk/src/media.cls.php#L1358
- plugins.trac.wordpress.org /browser/litespeed-cache/trunk/src/media.cls.php#L1317
- plugins.trac.wordpress.org /browser/litespeed-cache/trunk/src/media.cls.php#L777
- plugins.trac.wordpress.org /changeset/3635849/litespeed-cache/trunk/src/media.cls.php
- plugins.trac.wordpress.org /changeset?old_path=%2Flitespeed-cache/tags/7.8.1&new_path=%2Flitespeed-cache/tags/7.9
Sources
- CVE List CVE-2026-18978
- NVD CVE-2026-18978
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.