SSRF in Fluent Fluentd
CVE-2026-44161
Fluentd collects events from various data sources and writes them to files, RDBMS, NoSQL, IaaS, SaaS, Hadoop and so on. Prior to 1.19.3, the Fluentd out_http output plugin allows placeholders such as ${tag} in the endpoint configuration parameter, and if a placeholder value is derived from untrusted input an attacker can control the destination hostname of outbound HTTP requests and force requests to arbitrary internal services. This issue is fixed in version 1.19.3.
Vulnerability class: SSRF (Server-Side Request Forgery)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.2 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:L.
EPSS exploit prediction
EPSS: 0.004 (36.4th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 36th percentile — 36.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: 0.000
Affected products
- Fluent Fluentd — versions < 1.19.3
- Fluentd
Weakness classification (CWE)
References
- github.com/fluent/fluentd/security/advisories/GHSA-72f5-rr8c-r6gr (Mitigation, Vendor Advisory)
- github.com/fluent/fluentd/pull/5394 (Patch, Issue Tracking)
- github.com/fluent/fluentd/commit/c6a01ea2e0ea01977f8d615f7c6dbfae4cba88c9 (Patch)
- github.com/fluent/fluentd/releases/tag/v1.19.3 (Product, Release Notes)
Frequently asked questions
- What is CVE-2026-44161?
- CVE-2026-44161 is a high-severity vulnerability in Fluent Fluentd, classified under Server-Side Request Forgery (SSRF). CVSS score: 7.2/10. Published 2026-07-08.
- How severe is CVE-2026-44161?
- High severity. CVSS v3 base score is 7.2 out of 10.