XSS in Seraphinitesoft Seraphinite Accelerator
CVE-2026-17532
The Seraphinite Accelerator plugin for WordPress is vulnerable to Reflected Cross-Site Scripting via the 'seraph_accel_prep' parameter in versions up to, and including, 2.29.15. This is due to the CacheExtractPreparePageParams() function using PHP's loose inequality operator (!=) to compare the expected HMAC string against the JSON-decoded 'nonce' value — supplying the JSON boolean true causes any non-empty HMAC string to compare as loosely equal, bypassing the signature check — combined with insufficient output escaping in the _CbContentFinishSkip() function, which concatenates the attacker-controlled 'selfTest' field directly into the HTML response body. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that execute if they can successfully trick a user into performing an action such as clicking on a specially crafted link.
Vulnerability class: XSS (Cross-Site Scripting)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.
EPSS exploit prediction
EPSS: 0.008 (56.4th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 56th percentile — 56.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.008 · newest: 0.008 · change: 0.000
Affected products
- Seraphinitesoft Seraphinite Accelerator — versions 0
Weakness classification (CWE)
Public proof-of-concept exploits
References
- www.wordfence.com/threat-intel/vulnerabilities/id/5aeea62b-bd6c-4fe2-8c0f-8c991…
- plugins.trac.wordpress.org/browser/seraphinite-accelerator/tags/2.29.18/cache_e…
- plugins.trac.wordpress.org/browser/seraphinite-accelerator/tags/2.29.18/common…
- plugins.trac.wordpress.org/browser/seraphinite-accelerator/tags/2.29.18/cache.p…
- plugins.trac.wordpress.org/browser/seraphinite-accelerator/tags/2.29.15/cache_e…
- plugins.trac.wordpress.org/browser/seraphinite-accelerator/tags/2.29.15/common…
- plugins.trac.wordpress.org/browser/seraphinite-accelerator/tags/2.29.15/cache.p…
- plugins.trac.wordpress.org/changeset
- plugins.trac.wordpress.org/changeset
Frequently asked questions
- What is CVE-2026-17532?
- CVE-2026-17532 is a medium-severity vulnerability in Seraphinitesoft Seraphinite Accelerator, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2026-08-05.
- How severe is CVE-2026-17532?
- Medium severity. CVSS v3 base score is 6.1 out of 10.
- Is CVE-2026-17532 known to be exploited?
- 2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.