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

> Attackers can bypass SSRF protections via DNS rebinding to read internal network resources through elFinder's URL upload feature.

- **Severity:** High 8.6 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 31 Aug 2026
- **Updated:** 3 Sep 2026
- **Also known as:** GHSA-8x3q-jpjh-qh5c

## What is CVE-2026-81889?

CVE-2026-81889 is a high-severity server-side request forgery vulnerability in Studio-42 elFinder, published on 31 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### 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.

Weakness: CWE-918 (Server-Side Request Forgery)

## Which versions are affected by CVE-2026-81889?

2 open source packages ship an affected version, including studio-42/elfinder.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `studio-42/elfinder` | Packagist | All versions | 2.1.70 |
| `studio-42/elfinder` | Packagist | All versions | 2.1.70 |

## How do I fix CVE-2026-81889?

Upgrade studio-42/elfinder to 2.1.70 or later.

## Is CVE-2026-81889 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-81889 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-81889 and fix it if it is affected.

What it is: CVE-2026-81889 is a high-severity server-side request forgery vulnerability in Studio-42 elFinder, published on 31 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-81889 exists.

Affected packages and fixed versions:
- studio-42/elfinder (Packagist): affected all versions; fixed in 2.1.70
- studio-42/elfinder (Packagist): affected all versions; fixed in 2.1.70

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-81889/ (Markdown: https://insights.sbomify.com/CVE-2026-81889/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-81889
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-81889
- OSV: https://osv.dev/vulnerability/CVE-2026-81889

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-81889/
Summaries are generated and may contain mistakes; the official description above is the record.