CVE-2026-44161
highpriority · track · 0EPSS 0.004 · 38 %ileDEEUJPUSEPSS · scored 2026-10-27
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 ${tag} in the endpoint configuration parameter, and if a placeholder value is derived from untrusted input an attacker can control the destination hostname of outbound HTTP requests and force requests to arbitrary internal services. This issue is fixed in version 1.19.3.
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 6.6–7.2
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
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affected products (7)
Products and version ranges known to be affected.
advisories (5)
Vendor and ecosystem advisories describing this.
- WID-SEC-W-2026-2096Fluentd: Mehrere SchwachstellenDeutsch2026-06-25csaf · cert_bundDE
Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in Fluentd ausnutzen, um beliebigen Programmcode auszuführen, Informationen offenzulegen oder einen Denial of Service zu verursachen.
- WID-SEC-W-2026-4084Oracle Siebel CRM: Mehrere SchwachstellenDeutsch2026-10-20csaf · cert_bundDE
Ein entfernter, anonymer oder authentisierter Angreifer kann mehrere Schwachstellen in Oracle Siebel CRM ausnutzen, um die Vertraulichkeit, Integrität und Verfügbarkeit zu gefährden.
- GHSA-72f5-rr8c-r6grFluentd is Vulnerable to Server-Side Request Forgery (SSRF) via Placeholder Expansion in `out_http`2026-06-26ghsa · osvUS
The `out_http` output plugin allows the use of placeholders (such as `${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: 1. Avoid Dynamic Hostnames * Do not use the placeholder in the endpoint parameter as hostname. 2. 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. 3. Restrict allowed hosts * Inject filter to accept allowed hosts in placeholders explicitly if possible.
- BIT-fluentd-2026-44161Fluentd: Server-Side Request Forgery (SSRF) via Placeholder Expansion in `out_http`2026-07-14vendor · osvUS
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.
- JVNDB-2026-000090JVN iPedia advisory JVNDB-2026-0000902026-06-29vendor · jvndbJP
also known as (5)
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sources
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references (13)
External citations — patches, advisories, analysis.
- https://github.com/fluent/fluentd/commit/c6a01ea2e0ea01977f8d615f7c6dbfae4cba88c9cnnvd
- https://github.com/fluent/fluentd/pull/5394cnnvd
- https://github.com/fluent/fluentd/releasesPatchcnnvd
- https://github.com/fluent/fluentd/releases/tag/v1.19.3cnnvd
- https://github.com/fluent/fluentd/security/advisories/GHSA-72f5-rr8c-r6grcnnvd
- https://github.com/fluent/fluentd/commit/c6a01ea2e0ea01977f8d615f7c6dbfae4cba88c9enisa_euvd
- https://github.com/fluent/fluentd/pull/5394enisa_euvd
- https://github.com/fluent/fluentd/releases/tag/v1.19.3enisa_euvd
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