elFinder: Server-Side Request Forgery
CVE-2026-81889 is a high-severity server-side request forgery vulnerability in elFinder from Studio-42, with a CVSS 3.1 base score of 8.6 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected elFinder versions: < 2.1.70. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.55% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of elFinder you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on github.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- ChangedThe attack can reach beyond the vulnerable component into other systems.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- NoneNothing can be modified.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N. Scored by CNA (github.com).
Official 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: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Server-Side Request Forgery
The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.
How developers prevent this class of flaw
- If there is a known list of applications, IP, hostname, and/or domains to which the product is allowed to communicate, then use allowlists to ensure that outgoing requests are restricted to these known entities. The allowlists could be in the application code or possibly enforced by firewalls or network segmentation.
- If the product is expected to be able to connect to arbitrary IP addresses or domains, consider using a denylist that includes private network addresses, internal domain names, etc. The denylist could be in the application code or possibly enforced by firewalls or network segmentation.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Other vulnerabilities in elFinder
- 8.1 High severity
- 8.8 High severity
- 9.8 Critical severity
Recent Server-Side Request Forgery vulnerabilities
- 7.3 High severity
- 8.5 High severity
- 8.2 High severity
- 7.6 High severity
- 7.1 High severity
- 7.3 High severity
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