The `out_http` output plugin allows the use of placeholders (such as `${tag}`) in the `endpoint` configuration parameter. It was discovered that if the placeholder value is derived from untrusted user input, an attacker can maliciously control the destination hostname of the outbound HTTP requests made by Fluentd. ### Impact This vulnerability allows for a **Server-Side Request Forgery (SSRF)** attack. An unauthenticated attacker can force the Fluentd node to send HTTP requests to arbitrary internal services. This can lead to unauthorized access to internal APIs, data exfiltration, or the compromise of cloud metadata endpoints (e.g., AWS IMDS `169.254.169.254`). ### Patches v1.19.3 ### Workarounds If an immediate upgrade is not possible, users are strongly advised to apply the following mitigations: 1. Avoid Dynamic Hostnames * Do not use the placeholder in the endpoint parameter as hostname. 2. Restrict Network Access * Use firewall rules (e.g., iptables, AWS Security Groups) to block the Fluentd node from accessing sensitive internal IP addresses, specifically the cloud provider's metadata service and other internal microservices that Fluentd does not explicitly need to access. 3. Restrict allowed hosts * Inject filter to accept allowed hosts in placeholders explicitly if possible.
The `out_http` output plugin allows the use of placeholders (such as `${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.
Update fluentd to 1.19.3 if you use the affected versions. Test the change in a non-production environment first.
Local check
hol-guard supply-chain scanFluentd is Vulnerable to Server-Side Request Forgery (SSRF) via Placeholder Expansion in `out_http` affects fluentd (rubygems). Severity is high. 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.
AI coding agents often install or upgrade packages automatically in rubygems. A high vulnerability in a dependency can be pulled into a project through a normal install or update without a human reviewing the change, expanding the blast radius from a single package to every agent workspace that depends on it.
| Package | Affected range | Fixed version |
|---|---|---|
| fluentdrubygems | <=1.19.2 | 1.19.3 |
Fixed versions are reported by the source feed; confirm compatibility before updating.
Reported by GitHub Security Advisories (ghsa).
HOL Guard can help your team review package activity against supported protection paths.
Explore HOL GuardUpdate fluentd to 1.19.3 if you use the affected versions. Test the change in a non-production environment first.
Local check
hol-guard supply-chain scanFluentd is Vulnerable to Server-Side Request Forgery (SSRF) via Placeholder Expansion in `out_http` affects fluentd (rubygems). Severity is high. 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.
AI coding agents often install or upgrade packages automatically in rubygems. A high vulnerability in a dependency can be pulled into a project through a normal install or update without a human reviewing the change, expanding the blast radius from a single package to every agent workspace that depends on it.
| Package | Affected range | Fixed version |
|---|---|---|
| fluentdrubygems | <=1.19.2 | 1.19.3 |
Fixed versions are reported by the source feed; confirm compatibility before updating.
Reported by GitHub Security Advisories (ghsa).
HOL Guard can help your team review package activity against supported protection paths.
Explore HOL Guard