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CVE-2026-81889— elFinder: SSRF protection bypass via DNS rebinding in the `fsock_get_contents()` fallback

Quick assessment

Affected
Studio-42 elFinder
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Studio 42 elFinder是Studio 42团队的一款基于Web的文件管理组件。 Studio 42 elFinder 2.1.70之前版本存在服务端请求伪造漏洞，该漏洞源于在PHP cURL不可用时，URL上传功能中validate_address()与get_remote_contents()对主机名进行二次DNS解析，可被DNS重绑定绕过服务端请求伪造保护，导致内部HTTP响应体被存储为可读文件，并可能造成盲服务端请求伪造。

CVSS 8.6 · High EPSS 0.55% · P45

Affected Version Matrix 1

VendorProduct Version RangeStatus
Studio-42 elFinder < 2.1.70 affected
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I. Basic Information for CVE-2026-81889

Vulnerability Information
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Vulnerability Title
elFinder: SSRF protection bypass via DNS rebinding in the `fsock_get_contents()` fallback
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N
Source: CVE Program / CVE List V5
Vulnerability Type
服务端请求伪造(SSRF)
Source: CVE Program / CVE List V5
Vulnerability Title
Studio 42 elFinder 服务端请求伪造漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Studio 42 elFinder是Studio 42团队的一款基于Web的文件管理组件。 Studio 42 elFinder 2.1.70之前版本存在服务端请求伪造漏洞，该漏洞源于在PHP cURL不可用时，URL上传功能中validate_address()与get_remote_contents()对主机名进行二次DNS解析，可被DNS重绑定绕过服务端请求伪造保护，导致内部HTTP响应体被存储为可读文件，并可能造成盲服务端请求伪造。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
Studio-42 elFinder < 2.1.70 -

II. Public POCs for CVE-2026-81889

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III. Intelligence Information for CVE-2026-81889

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Patches & Fixes for CVE-2026-81889 (2)

Vendor Advisories for CVE-2026-81889 (1)

Vendor Pages for CVE-2026-81889 (1)

Same Patch Batch · Studio-42 · 2026-08-31 · 3 CVEs total

CVE-2026-81891 8.1 HIGH elFinder: ZIP extraction bypasses uploadDeny MIME filter allowing PHP file upload (RCE)
CVE-2026-81890 5.4 MEDIUM elFinder: CSRF in netmount allows forced FTP mounts and server-side FTP connections

IV. Related Vulnerabilities

Same product: elFinder
Same vendor: Studio-42
Same weakness: CWE-918

V. Comments for CVE-2026-81889

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