CVE-2024-45302 CRLF Injection in RestSharp's `RestRequest.AddHeader` method
CRLF injection in RestSharp allows attackers to inject headers or split requests, potentially leading to Server-Side Request Forgery in consuming applications.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2024-45302?
CVE-2024-45302 is a medium-severity server-side request forgery vulnerability in RestSharp, published on 29 Aug 2024. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Official description
RestSharp is a Simple REST and HTTP API Client for .NET. The second argument to `RestRequest.AddHeader` (the header value) is vulnerable to CRLF injection. The same applies to `RestRequest.AddOrUpdateHeader` and `RestClient.AddDefaultHeader`. The way HTTP headers are added to a request is via the `HttpHeaders.TryAddWithoutValidation` method which does not check for CRLF characters in the header value. This means that any headers from a `RestSharp.RequestHeaders` object are added to the request in such a way that they are vulnerable to CRLF-injection. In general, CRLF-injection into a HTTP header (when using HTTP/1.1) means that one can inject additional HTTP headers or smuggle whole HTTP requests. If an application using the RestSharp library passes a user-controllable value through to a header, then that application becomes vulnerable to CRLF-injection. This is not necessarily a security issue for a command line application like the one above, but if such code were present in a web application then it becomes vulnerable to request splitting (as shown in the PoC) and thus Server Side Request Forgery. Strictly speaking this is a potential vulnerability in applications using RestSharp, not in RestSharp itself, but I would argue that at the very least there needs to be a warning about this behaviour in the RestSharp documentation. RestSharp has addressed this issue in version 112.0.0. All users are advised to upgrade. There are no known workarounds for this vulnerability.
Which versions are affected by CVE-2024-45302?
2 open source packages ship an affected version, including RestSharp. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
RestSharp NuGet | From 107.0.0-preview.1 | 112.0.0 |
RestSharp NuGet | From 107.0.0-preview.1 | 112.0.0 |
Products include Restsharp Restsharp.
How do I fix CVE-2024-45302?
Upgrade RestSharp to 112.0.0 or later.
Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.
Is CVE-2024-45302 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2024-45302 exists.
Other vulnerabilities in RestSharp
Sources
Also known as GHSA-4rr6-2v9v-wcpc.