TTPwire Vol. 1 · MITRE ATT&CK·Tagged

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Wordfence Blog

Attackers Actively Exploiting Critical Vulnerability in Ninja Forms – File Upload Plugin

István Márton · 2026-04-16 · Read original ↗

ATT&CK techniques detected

11 predictions
T1190Exploit Public-Facing Application
98%
“. 160. 202. 35. 137 over 1, 300 blocked requests. indicators of compromise the attackers are attempting to upload malicious. php or. htaccess files onto websites. it is recommended to review the webroot and / wp - content / uploads directories for any suspicious or unknown php fi…”
T1190Exploit Public-Facing Application
97%
“of exploits blocked the wordfence firewall has blocked over 118, 600 exploit attempts since the vulnerability was publicly disclosed. according to our data, attackers started targeting websites the same day the vulnerability was disclosed, on april 6th. we also detected and block…”
T1190Exploit Public-Facing Application
97%
“attackers actively exploiting critical vulnerability in ninja forms – file upload plugin on april 6th, 2026, we publicly disclosed a critical arbitrary file upload vulnerability in ninja forms – file upload, a wordpress plugin with an estimated 50, 000 active installations. this …”
T1190Exploit Public-Facing Application
95%
“3. 3. 26. this makes it possible for unauthenticated attackers to upload arbitrary files on the affected site ' s server which may make remote code execution possible. note : the vulnerability was partially patched in version 3. 3. 25 and fully patched in version 3. 3. 27. more d…”
T1190Exploit Public-Facing Application
94%
“, 2026. considering this vulnerability is being actively exploited, we urge users to ensure their sites are updated with the latest patched version of ninja forms – file upload, version 3. 3. 27 at the time of this writing, as soon as possible. vulnerability summary from wordfenc…”
T1190Exploit Public-Facing Application
91%
“audit from our professional team of wordpress security experts. get immediate help with malware removal the post attackers actively exploiting critical vulnerability in ninja forms – file upload plugin appeared first on wordfence.”
T1190Exploit Public-Facing Application
83%
“we detailed the vulnerability : 50, 000 wordpress sites affected by arbitrary file upload vulnerability in ninja forms – file upload wordpress plugin a closer look at the attack data the following data highlights actual exploit attempts from threat actors targeting this vulnerabi…”
T1190Exploit Public-Facing Application
67%
“severity arbitrary file upload vulnerability in the ninja forms – file upload plugin that allows unauthenticated threat actors to upload arbitrary files and achieve remote code execution. our threat intelligence indicates that attackers started actively targeting this vulnerabili…”
T1204.002Malicious File
53%
“##ing the source validation check while the following instructions added to a. htaccess file would result in text files being treated as php files. forcetype application / octet - stream addtype application / x - httpd - php. txt header set content - disposition attachment < file…”
T1190Exploit Public-Facing Application
42%
“##tected and unpatched. if you believe your site has been compromised as a result of this vulnerability or any other vulnerability, we offer incident response services via wordfence care. if you need your site cleaned immediately, wordfence response offers the same service with 2…”
T1505.003Web Shell
42%
“##kes php _ uname ( ) in order to obtain information about the specifics of the operating system and host the script is located on. this function is a common choice in minimal shells because it is a single call with high value output. unlike system ( ) or exec ( ) it is less like…”

Summary

On April 6th, 2026, we publicly disclosed a critical Arbitrary File Upload vulnerability in Ninja Forms – File Upload, a WordPress plugin with an estimated 50,000 active installations. This vulnerability can be leveraged by unauthenticated attackers to upload arbitrary files, including PHP backdoors, and achieve remote code execution.

The post Attackers Actively Exploiting Critical Vulnerability in Ninja Forms – File Upload Plugin appeared first on Wordfence.