Server-Side Request Forgery (SSRF) in Fluentd - CVE-2026-44161
Published: June 29, 2026
Vulnerability identifier: #VU135830
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:L/SC:L/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-44161
CWE-ID: CWE-918
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Fluentd Project
Affected software:
Fluentd
Fluentd
Detailed vulnerability description
The vulnerability allows a remote attacker to perform server-side request forgery.
The vulnerability exists due to server-side request forgery in the out_http endpoint configuration parameter when expanding placeholders derived from untrusted user input. A remote attacker can supply a crafted placeholder value to perform server-side request forgery.
This can cause outbound HTTP requests to be sent to internal services or cloud metadata endpoints.
How to mitigate CVE-2026-44161
Install security update from vendor's website.