CVE-2026-44161 is a high-severity server-side request forgery (SSRF) vulnerability in fluentd (rubygems), affecting versions <= 1.19.2. It is fixed in 1.19.3.
The out_http output plugin allows the use of placeholders (such as ${tag}) in the endpoint configuration parameter. It was discovered that if the placeholder value is derived from untrusted user input, an attacker can maliciously control the destination hostname of the outbound HTTP requests made by Fluentd. Impact This vulnerability allows for a Server-Side Request Forgery (SSRF) attack. An unauthenticated attacker can force the Fluentd node to send HTTP requests to arbitrary internal services. This can lead to unauthorized access to internal APIs, data exfiltration, or the compromise of cloud metadata endpoints (e.g., AWS IMDS 169.254.169.254). Patches v1.19.3 Workarounds If an immediate upgrade is not possible, users are strongly advised to apply the following mitigations: Avoid Dynamic Hostnames Do not use the placeholder in the endpoint parameter as hostname. Restrict Network Access Use firewall rules (e.g., iptables, AWS Security Groups) to block the Fluentd node from accessing sensitive internal IP addresses, specifically the cloud provider's metadata service and other internal microservices that Fluentd does not explicitly need to access. Restrict allowed hosts Inject filter to accept allowed hosts in placeholders explicitly if possible.
Untrusted input controls the target URL of a server-initiated request, which may reach internal services not otherwise accessible from outside. Typical impact: access to internal metadata services, internal APIs, or cloud credentials.
CVE-2026-44161 has a CVSS score of 7.2 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment.
A fixed version is available (1.19.3). Upgrading removes the vulnerable code path.
rubygems
fluentd (<= 1.19.2)fluentd → 1.19.3 (rubygems)Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter instead of chasing every advisory.
Kodem's runtime-powered SCA identifies whether CVE-2026-44161 is reachable in your applications. Explore open-source security for your team.
See if CVE-2026-44161 is reachable in your applications. Get a demo
Already deployed Kodem? See CVE-2026-44161 in your environment →Upgrade fluentd to 1.19.3 or later to resolve this vulnerability.
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
CVE-2026-44161 is a high-severity server-side request forgery (SSRF) vulnerability in fluentd (rubygems), affecting versions <= 1.19.2. It is fixed in 1.19.3. Untrusted input controls the target URL of a server-initiated request, which may reach internal services not otherwise accessible from outside.
CVE-2026-44161 has a CVSS score of 7.2 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
fluentd (rubygems) versions <= 1.19.2 is affected.
Yes. CVE-2026-44161 is fixed in 1.19.3. Upgrade to this version or later.
Whether CVE-2026-44161 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
Upgrade fluentd to 1.19.3 or later.