CVE-2026-4895: The GreenShift - Animation and Page Builder Blocks plugin for WordPress is vulnerable to Stored Cross-Site Scripting in versions up to, and including,...

Description

The GreenShift - Animation and Page Builder Blocks plugin for WordPress is vulnerable to Stored Cross-Site Scripting in versions up to, and including, 12.8.9 This is due to insufficient input sanitization and output escaping in the gspb_greenShift_block_script_assets() function. The function uses str_replace() to insert 'fetchpriority="high"' before 'src=' attributes when processing greenshift-blocks/image blocks with the disablelazy attribute enabled. Because this replacement operates on the entire HTML string without parsing, contributors can inject the string 'src=' into HTML attribute values (such as class attributes). When the str_replace executes, the double quotes in the replacement string break out of the attribute context, allowing injection of malicious HTML attributes like onfocus with JavaScript payloads. This makes it possible for authenticated attackers, with contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.

Metrics

CVSS 3.1

6.4/10

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

EPSS Probability

0.42%

33.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-79

References

Timeline

Published: Apr 11, 2026
Last Modified: Jun 17, 2026
Status: Deferred

Frequently Asked Questions

What is CVE-2026-4895?

The GreenShift - Animation and Page Builder Blocks plugin for WordPress is vulnerable to Stored Cross-Site Scripting in versions up to, and including, 12.8.9 This is due to insufficient input sanitization and output escaping in the gspb_greenShift_block_script_assets() function. The function uses str_replace() to insert 'fetchpriority="high"' before 'src=' attributes when processing greenshift-blocks/image blocks with the disablelazy attribute enabled. Because this replacement operates on the entire HTML string without parsing, contributors can inject the string 'src=' into HTML attribute values (such as class attributes). When the str_replace executes, the double quotes in the replacement string break out of the attribute context, allowing injection of malicious HTML attributes like onfocus with JavaScript payloads. This makes it possible for authenticated attackers, with contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.

How severe is CVE-2026-4895?

CVE-2026-4895 has a CVSS score of 6.4/10 (MEDIUM severity). The EPSS model estimates a 0.42% probability of exploitation in the next 30 days.

How do I fix CVE-2026-4895?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.