CVE-2026-17532

Seraphinite Accelerator <= 2.29.18 - Reflected Cross-Site Scripting

2026-08-04 18:25
Alireza

Strategic Overview

Status
Patched in 2.29.19
Affected Plugin
Seraphinite Accelerator
Affected Version
<= 2.29.18
CVSS
6.1Medium
Weakness type
CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CVE
CVE-2026-17532
View all Seraphinite Accelerator vulnerabilities

At a glance

CVE-2026-17532 is a medium-severity Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in the Seraphinite Accelerator WordPress plugin, affecting versions <= 2.29.18. It carries a CVSS score of 6.1 (reachable over the network; low attack complexity). Exploitation requires no authentication. The issue is fixed in version 2.29.19; sites on affected versions should update now. Disclosed August 2026, reported by Alireza.

Vulnerability Overview

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.

Technical Analysis

The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no privileges on the target site.

CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Seraphinite Accelerator <= 2.29.18 carries this weakness at seraph_accel_prep, and reaching it takes a caller who can reach the endpoint. Cross-site scripting happens when input from a request is written into a page without being escaped for the context it lands in, so the browser parses attacker-supplied text as markup or script.

Injected script runs with the privileges of whoever views the affected page, which is how these flaws turn into administrator session theft, silent account creation or persistent backdoors in page content. For Seraphinite Accelerator the fix is 2.29.19: builds <= 2.29.18 are affected, anything from 2.29.19 onward is not.

Remediation

Update to version 2.29.19, or a newer patched version

How WordSec helps

The attempt arrives as an ordinary request to Seraphinite Accelerator: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: Seraphinite Accelerator 2.29.19 closes this, and updating the plugin is the step that ends it.

  • Firewall
  • Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2026-17532https://www.wordfence.com/threat-intel/vulnerabilities/id/5aeea62b-bd6c-4fe2-8c0f-8c9919688e87https://nvd.nist.gov/vuln/detail/CVE-2026-17532

Related records

Vulnerability data © Defiant, Inc., provided under the Wordfence Intelligence T&C