Fider: Server-Side Request Forgery via webhook URLs
Summary
Fider, a self-hosted feedback portal, validates webhook URLs only for format before the server fetches them. An attacker with an administrative account can make the Fider server send HTTP requests to internal services, localhost or cloud metadata endpoints, which can expose internal data and cloud credentials. The CVSS vector lists low privileges, while the description says administrative privileges are required; CVSS score is 7.1 (High).
Affected
- Fider versions before 0.34.0 (CNA: affected < 0.34.0)
- VulDB describes the range as up to 0.33.x
Fixed in
- 0.34.0 (vendor fix, PR #1494, GHSA-g445-xwm7-594r)
- Latest release recommended: a related DNS-rebinding issue (CVE-2026-102877) is reported fixed in 0.38.0 (not verified against the vendor page)
Workaround
Unknown. No vendor workaround is documented. Interim measures until patched:
- Limit administrator rights to trusted accounts.
- Restrict outbound traffic from the Fider host to internal ranges and metadata addresses (169.254.169.254).
- Review existing webhooks for unexpected targets.
Exploitation
- Not known to be exploited in the wild (no evidence found).
- No public proof of concept found; VulDB states that no exploit is available.
- NVD analysis pending.
Our recommendation
- Update Fider to the latest release, not only 0.34.0.
- Review administrator accounts and remove unneeded ones.
- Check existing webhook URLs for internal or metadata targets.
- Restrict outbound traffic from the Fider host and monitor for unusual requests.
- Prioritise this on cloud-hosted instances or where internal services are reachable from the host.
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- CVE Record CVE-2026-65967 www.cve.org
- GitHub Security Advisory GHSA-g445-xwm7-594r github.com
- Fider Release v0.34.0 github.com
- VulDB entry 435953 vuldb.com
- OffSeq Threat Radar: CVE-2026-65967 radar.offseq.com
- NixOS nixpkgs issue on related Fider SSRF fix github.com
Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 11 Nov 2026, 20:37.
Original description (NVD)
Fider is a feedback portal for feature requests and suggestions. Prior to version 0.34.0, a Server-Side Request Forgery (SSRF) vulnerability exists in Fider due to insufficient validation of webhook URLs. The application allows user-controlled URLs to be fetched by the server without restricting access to internal or external network resources. This enables attackers with administrative privileges to make arbitrary HTTP requests from the server, potentially accessing internal services or cloud metadata endpoints. This issue has been patched in version 0.34.0.
Sources
The tracker combines official, freely usable data sources – updated continuously:
- NVD (NIST) – CVEs, rating (CVSS), affected products
- CISA KEV – vulnerabilities confirmed by CISA as actively exploited
- CISA Vulnrichment – CISA assessment (SSVC) in the official CVE record
- FIRST EPSS – probability of exploitation
- Microsoft MSRC – Patch Tuesday: vulnerabilities, severity, updates
- PoC-in-GitHub – public proof-of-concept repositories
- Metasploit (Rapid7) – modules of the Metasploit Framework
- Exploit-DB (OffSec) – archive of public exploits (links only)
- Patch days: official vendor pages (linked per vendor) (Vendor patch days)
This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.
Affected? We can help.
We check whether your systems are affected, install updates and close the gap – continuously with the System Health Checker if you wish.