vulnerability / NVI-00017585 / Revision 1
chi Middleware Vulnerable to Potential IP Spoofing via `X-Forwarded-For` Header in `Request.RemoteAddr` Resolution
GitHub lists this reviewed advisory for github.com/go-chi/chi/middleware, github.com/go-chi/chi/v2/middleware, github.com/go-chi/chi/v3/middleware, github.com/go-chi/chi/v4/middleware, github.com/go-chi/chi/v5/middleware. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.
This report has not inspected your inventory, configuration, deployed build, reachability or evidence. A catalog listing and a severity score do not establish exposure or compromise.
01 / Meaning
Why it matters
Published affected context helps an owner decide what evidence to gather. This report has not examined your application.
02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
github.com/go-chi/chi/middleware
source listed>= 0.9.0, <= 1.5.5
### Summary The vulnerability allows the `Request.RemoteAddr` to be spoofed when determining the request source IP via the `X-Forwarded-For` header. This could result in misidentification of the request source and potentially compromise access control and logging integrity. ### Details Currently, the `RealIP()` implementation splits the `X-Forwarded-For` header by `,` and uses the first IP. https://github.com/go-chi/chi/blob/v5.1.0/middleware/realip.go#L50-L54 However, relying on the first IP in the `X-Forwarded-For` header is insecure because it can be manipulated by attackers to falsify the source IP. Malicious Case: 1. A malicious client sends a request with a forged IP in the X-Forwarded-For header: `X-Forwarded-For: ` 2. The proxy appends the actual client’s IP and forwards the request: `X-Forwarded-For: ,` 3. If the server always uses the first IP, it becomes vulnerable to IP spoofing. Ideally, the implementation should verify IPs starting from the end of the `X-Forwarded-For` header value, skipping trusted IPs within the system, and using the first untrusted IP as the actual client IP. For example, the `labstack/echo` web framework proce
github.com/go-chi/chi/v2/middleware
source listed<= 2.1.1
### Summary The vulnerability allows the `Request.RemoteAddr` to be spoofed when determining the request source IP via the `X-Forwarded-For` header. This could result in misidentification of the request source and potentially compromise access control and logging integrity. ### Details Currently, the `RealIP()` implementation splits the `X-Forwarded-For` header by `,` and uses the first IP. https://github.com/go-chi/chi/blob/v5.1.0/middleware/realip.go#L50-L54 However, relying on the first IP in the `X-Forwarded-For` header is insecure because it can be manipulated by attackers to falsify the source IP. Malicious Case: 1. A malicious client sends a request with a forged IP in the X-Forwarded-For header: `X-Forwarded-For: ` 2. The proxy appends the actual client’s IP and forwards the request: `X-Forwarded-For: ,` 3. If the server always uses the first IP, it becomes vulnerable to IP spoofing. Ideally, the implementation should verify IPs starting from the end of the `X-Forwarded-For` header value, skipping trusted IPs within the system, and using the first untrusted IP as the actual client IP. For example, the `labstack/echo` web framework proce
github.com/go-chi/chi/v3/middleware
source listed<= 3.3.5
### Summary The vulnerability allows the `Request.RemoteAddr` to be spoofed when determining the request source IP via the `X-Forwarded-For` header. This could result in misidentification of the request source and potentially compromise access control and logging integrity. ### Details Currently, the `RealIP()` implementation splits the `X-Forwarded-For` header by `,` and uses the first IP. https://github.com/go-chi/chi/blob/v5.1.0/middleware/realip.go#L50-L54 However, relying on the first IP in the `X-Forwarded-For` header is insecure because it can be manipulated by attackers to falsify the source IP. Malicious Case: 1. A malicious client sends a request with a forged IP in the X-Forwarded-For header: `X-Forwarded-For: ` 2. The proxy appends the actual client’s IP and forwards the request: `X-Forwarded-For: ,` 3. If the server always uses the first IP, it becomes vulnerable to IP spoofing. Ideally, the implementation should verify IPs starting from the end of the `X-Forwarded-For` header value, skipping trusted IPs within the system, and using the first untrusted IP as the actual client IP. For example, the `labstack/echo` web framework proce
github.com/go-chi/chi/v4/middleware
source listed<= 4.1.3
### Summary The vulnerability allows the `Request.RemoteAddr` to be spoofed when determining the request source IP via the `X-Forwarded-For` header. This could result in misidentification of the request source and potentially compromise access control and logging integrity. ### Details Currently, the `RealIP()` implementation splits the `X-Forwarded-For` header by `,` and uses the first IP. https://github.com/go-chi/chi/blob/v5.1.0/middleware/realip.go#L50-L54 However, relying on the first IP in the `X-Forwarded-For` header is insecure because it can be manipulated by attackers to falsify the source IP. Malicious Case: 1. A malicious client sends a request with a forged IP in the X-Forwarded-For header: `X-Forwarded-For: ` 2. The proxy appends the actual client’s IP and forwards the request: `X-Forwarded-For: ,` 3. If the server always uses the first IP, it becomes vulnerable to IP spoofing. Ideally, the implementation should verify IPs starting from the end of the `X-Forwarded-For` header value, skipping trusted IPs within the system, and using the first untrusted IP as the actual client IP. For example, the `labstack/echo` web framework proce
github.com/go-chi/chi/v5/middleware
source listed< 5.3.0
### Summary The vulnerability allows the `Request.RemoteAddr` to be spoofed when determining the request source IP via the `X-Forwarded-For` header. This could result in misidentification of the request source and potentially compromise access control and logging integrity. ### Details Currently, the `RealIP()` implementation splits the `X-Forwarded-For` header by `,` and uses the first IP. https://github.com/go-chi/chi/blob/v5.1.0/middleware/realip.go#L50-L54 However, relying on the first IP in the `X-Forwarded-For` header is insecure because it can be manipulated by attackers to falsify the source IP. Malicious Case: 1. A malicious client sends a request with a forged IP in the X-Forwarded-For header: `X-Forwarded-For: ` 2. The proxy appends the actual client’s IP and forwards the request: `X-Forwarded-For: ,` 3. If the server always uses the first IP, it becomes vulnerable to IP spoofing. Ideally, the implementation should verify IPs starting from the end of the `X-Forwarded-For` header value, skipping trusted IPs within the system, and using the first untrusted IP as the actual client IP. For example, the `labstack/echo` web framework proce
03 / Response
What to do next
- investigate
Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. GitHub Advisory Database
A fixed release is not deployment evidence.
Check current vendor support and compatibility. After making a change, verify the deployed build and relevant runtime conditions. Keep the evidence, owner and time. An updated lockfile alone does not prove what is running.
04 / Limits
What this report cannot establish
- Customer inventory, deployment, reachability and exploitation have not been inspected.
05 / Provenance
Sources you can inspect
Each assertion retains its source. Mirrored records may repeat one underlying publisher; additional links are not independent corroboration.
- GHSA-9g5q-2w5x-hmxf ↗
GitHub Advisory Database · vendor advisory
Observed . GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.
Public revision history
Only published revisions appear here. Routine fetches do not create a material-change event.
- Revision 1 ·
First indexed by Null; source disclosure date is shown separately.