CVE-2026-81889
elFinder: SSRF protection bypass via DNS rebinding in the `fsock_get_contents()` fallback
- State
- Published
- Severity
- 8.6 High
- Published
- Aug 31, 2026
- Updated
- Sep 3, 2026
- Reserved
- Aug 27, 2026
Description
elFinder is an open-source file manager for web, written in JavaScript using jQuery UI. Prior to 2.1.70, elFinder URL uploads in php/elFinder.class.php can bypass server-side request forgery protections when PHP cURL is unavailable because validate_address() validates $info['ip'], but get_remote_contents() selects fsock_get_contents(), which connects to $arr['host'] and performs a second DNS resolution. An attacker able to submit a URL upload can use DNS rebinding to have the first resolution return a public address and the connection resolution return a loopback or private address, causing the internal HTTP response body to be stored as an uploaded file and made readable through elFinder. After a successful fetch, get_headers($url, true) separately requests the original hostname without reusing the validated and pinned connection, creating an additional blind server-side request forgery path even when curl_get_contents() is selected. This issue is fixed in version 2.1.70.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 8.6 High | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N | GitHub_M |
Weaknesses
- CWE-918 Server-Side Request Forgery (SSRF)
Affected Products
| Product | Versions |
|---|---|
elFinderStudio-42 |
|
References
- https://github.com/Studio-42/elFinder/security/advisories/GHSA-8x3q-jpjh-qh5c
- https://github.com/Studio-42/elFinder/commit/191372c1bbebbd36fb55af79a84b9984861390ff
- https://github.com/Studio-42/elFinder/commit/6d997386cd0f1abab4706c220b46b0aea0ecff51
- https://github.com/Studio-42/elFinder/releases/tag/2.1.70
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