What is the CVSS score of CVE-2026-5217?

CVE-2026-5217 has a CVSS 3.1 base score of 7.2 (High). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N. EPSS exploitation probability: 0.1%.

Which versions of PHP are affected by CVE-2026-5217?

Optimole WordPress plugin versions 4.2.2 and earlier contain a stored cross-site scripting vulnerability in the REST API that allows unauthenticated attackers to inject and persistently execute…

How to fix or mitigate CVE-2026-5217?

Within 24 hours: Disable or remove Optimole plugin ≤4.2.2 immediately; if critical to operations, restrict REST API access via .htaccess or firewall rules to trusted IPs only. Within 7 days: Monitor WordPress options table and transients for suspicious entries; audit admin accounts for unauthorized activity; review access logs for /wp-json/optimole/v1/optimizations requests. Within 30 days: Identify and upgrade to patched version when vendor releases fix; conduct content security policy (CSP) audit; implement Web Application Firewall rules to sanitize REST API inputs.

PHP CVE-2026-5217

EUVD-2026-21662 HIGH

Cross-site Scripting (XSS) (CWE-79)

2026-04-11 Wordfence

GHSA-8g9h-q4wq-r7gp

XSS PHP WordPress

7.2

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

7.2 HIGH

AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

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

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Changed

Confidentiality

Low

Integrity

Low

Availability

None

Lifecycle Timeline

Re-analysis Queued

Apr 24, 2026 - 18:07 vuln.today

cvss_changed

EUVD ID Assigned

Apr 11, 2026 - 01:30 euvd

EUVD-2026-21662

Analysis Generated

Apr 11, 2026 - 01:30 vuln.today

CVE Published

Apr 11, 2026 - 01:24 nvd

HIGH 7.2

DescriptionCVE.org

The Optimole - Optimize Images | Convert WebP & AVIF | CDN & Lazy Load | Image Optimization plugin for WordPress is vulnerable to Stored Cross-Site Scripting in all versions up to, and including, 4.2.2. This is due to insufficient input sanitization and output escaping on the user-supplied 's' parameter (srcset descriptor) in the unauthenticated /wp-json/optimole/v1/optimizations REST endpoint. The endpoint validates requests using an HMAC signature and timestamp, but these values are exposed directly in the frontend HTML making them accessible to any visitor. The plugin uses sanitize_text_field() on the descriptor value of rest.php, which strips HTML tags but does not escape double quotes. The poisoned descriptor is then stored via transients (backed by the WordPress options table) and later retrieved and injected verbatim into the srcset attribute of tag_replacer.php without proper escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts into pages that will execute whenever a user accesses the injected page.

AnalysisAI

Unauthenticated stored XSS in Optimole WordPress plugin (≤4.2.2) allows attackers to inject malicious scripts via the srcset descriptor parameter in the /wp-json/optimole/v1/optimizations REST endpoint. Despite HMAC signature validation, authentication tokens are exposed in frontend HTML, enabling exploitation. Injected payloads persist in WordPress options table via transients and execute when victim browsers render affected pages. No public exploit identified at time of analysis.

Technical ContextAI

Insufficient output escaping on srcset descriptor values after sanitize_text_field() processing. Double quotes in user input bypass sanitization, enabling attribute-context XSS when transient-stored descriptors are injected into <img> srcset attributes in tag_replacer.php without proper escaping. CWE-79 manifests through inadequate contextual output encoding in REST API->transient->frontend rendering chain.

RemediationAI

Upstream fix available in WordPress plugin repository code (commits visible in Trac refs); released patched version not independently confirmed. Monitor vendor advisory at https://www.wordfence.com/threat-intel/vulnerabilities/id/50417068-339a-4ae5-9c90-8f08f54ce0af?source=cve for official release announcement. As interim mitigation, disable the Optimole plugin until patched version is confirmed available. If plugin use is mandatory, implement Web Application Firewall rules to block requests to /wp-json/optimole/v1/optimizations containing double-quote characters in 's' parameter values, though this may impact legitimate functionality.