CVE-2026-5217 json
Optimole <= 4.2.2 - Unauthenticated Stored Cross-Site Scripting via Srcset Descriptor Parameter
published 2026-04-11 6 mo ago modified 2026-06-17 4 mo ago also EUVD-2026-21662
- cvss
- 7.2
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.5%
- EPSS 0.5% chance of exploitation in 30 days, percentile 39%
- public exploits
- 0
- none known
Summary
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.
CISA SSVC
- Exploitation
- none
- Automatable
- yes
- Technical impact
- partial
- Assessed
- 6 mo ago
Exploit prediction
0.46% chance of exploitation in the next 30 days, higher than 39% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 7.2 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N |
Affected products
- optimole Optimole – Optimize Images in Real Time
Classification
- Weakness
-
- CWE-79 Improper Neutralization of Input During Web Page Generation
- Technology feeds
References
- wordfence.com /threat-intel/vulnerabilities/id/50417068-339a-4ae5-9c90-8f08f54ce0af?source=cve
- plugins.trac.wordpress.org /browser/optimole-wp/trunk/inc/rest.php#L159
- plugins.trac.wordpress.org /browser/optimole-wp/trunk/inc/rest.php#L1008
- plugins.trac.wordpress.org /browser/optimole-wp/trunk/inc/tag_replacer.php#L526
- plugins.trac.wordpress.org /browser/optimole-wp/tags/4.2.1/inc/tag_replacer.php#L526
- plugins.trac.wordpress.org /browser/optimole-wp/tags/4.2.1/inc/rest.php#L1008
- plugins.trac.wordpress.org /browser/optimole-wp/tags/4.2.1/inc/rest.php#L159
Sources
- CVE List CVE-2026-5217
- NVD CVE-2026-5217
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.
CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.