CVE-2026-35569

Apostrophecms cross-site scripting (XSS)

8.7 HIGHPublic exploitEPSS 0.44%

Published15 Apr 2026

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 breakdown

Attack vectorNetwork

Attack complexityLow

Privileges requiredLow

User interactionRequired

ScopeChanged

ConfidentialityHigh

IntegrityHigh

AvailabilityNone

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

Affected products

Apostrophecms< 4.29.0

Remediation

Fixed in

Apostrophecms≥ 4.29.0

Patch & vendor advisories

References

Related CVEs

Recent high-severity vulnerabilities sharing a weakness type.

Frequently asked

Is CVE-2026-35569 being actively exploited?

CVE-2026-35569 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 0.44%.

How severe is CVE-2026-35569?

CVE-2026-35569 has a CVSS 3.1 base score of 8.7, rated high. EPSS estimates a 0.44% probability of exploitation.

Which products are affected by CVE-2026-35569?

Affected products include Apostrophecms.

How do I fix CVE-2026-35569?

Upgrade affected software to a fixed version, for example Apostrophecms 4.29.0 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-35569 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.