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Vulnerability record · CVE-2026-35569 · published 15 April 2026

CVE-2026-35569: Apostrophecms cross-site scripting vulnerability

Apostrophecms · Apostrophecms

ApostropheCMS is an open-source Node.js content management system. Versions 4.28.0 and prior contain a stored cross-site scripting vulnerability in SEO-related fields (SEO Title and Meta Description), where user-controlled input is rendered without proper output encoding into HTML contexts including <title> tags, <meta> attributes, and JSON-LD structured data. An attacker can inject a payload such as "></title><script>alert(1)</script> to break out of the intended HTML context and execute arbitrary JavaScript in the browser of any authenticated user who views the affected page. This can be leveraged to perform authenticated API requests, access sensitive data such as usernames, email addresses, and roles via internal APIs, and exfiltrate it to an attacker-controlled server. This issue has been fixed in version 4.29.0.

8.7 CVSS 3.1 High EPSS 0.44% · top 64.3% CWE-79 · Cross-site scriptingCWE-116 · CWE-116
8.7CVSS 3.1 base score
0.44%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
3References, 1 tagged exploit
17 Jun 2026Last modified by NVD

Description

ApostropheCMS is an open-source Node.js content management system. Versions 4.28.0 and prior contain a stored cross-site scripting vulnerability in SEO-related fields (SEO Title and Meta Description), where user-controlled input is rendered without proper output encoding into HTML contexts including <title> tags, <meta> attributes, and JSON-LD structured data. An attacker can inject a payload such as "></title><script>alert(1)</script> to break out of the intended HTML context and execute arbitrary JavaScript in the browser of any authenticated user who views the affected page. This can be leveraged to perform authenticated API requests, access sensitive data such as usernames, email addresses, and roles via internal APIs, and exfiltrate it to an attacker-controlled server. This issue has been fixed in version 4.29.0.

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/Chittu13/cve-research/tree/main/CVE-2026-35569
https://github.com/apostrophecms/apostrophe/commit/0e57dd07a56ae1ba1e3af646ba026db4d0ab5bb3 Patch
https://github.com/apostrophecms/apostrophe/security/advisories/GHSA-855c-r2vq-c292 ExploitPatchVendor Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2026-35569), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.