CVE-2026-81891 is a high-severity (CVSS 8.1) Unrestricted File Upload vulnerability. O3 Security confirms whether CVE-2026-81891 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
elFinder is an open-source file manager for web, written in JavaScript using jQuery UI. Prior to 2.1.70, checkExtractItems() in php/elFinderVolumeDriver.class.php calls mimetypeInternalDetect()…
Description
elFinder is an open-source file manager for web, written in JavaScript using jQuery UI. Prior to 2.1.70, checkExtractItems() in php/elFinderVolumeDriver.class.php calls mimetypeInternalDetect() without passing the result through mimeTypeNormalize(). Because the .phtml, .phar, .php5, and .php3 extensions are absent from mime.types, the staticMimeMap entries that map them to text/x-php are not applied, and allowPutMime() permits extraction even when uploadDeny blocks text/x-php. An attacker with ZIP upload permission can extract PHP-executable files into a web-accessible files/ directory and achieve remote code execution when the server executes those extensions. This issue is fixed in version 2.1.70.
Detection & mitigation playbook
VulnerabilityDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for the affected component. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Remediation status
No patched version of the affected component has shipped for CVE-2026-81891 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-81891 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-81891. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-81891 in your dependencies?
O3 detects CVE-2026-81891 across dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.