CVE-2020-26281 request smuggling in async-h1
Attackers can smuggle HTTP requests to forge headers or capture other users' data in Rust web servers using async-h1 behind a reverse proxy.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2020-26281?
CVE-2020-26281 is a medium-severity vulnerability in http-rs async-h1, published on 21 Dec 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
async-h1 is an asynchronous HTTP/1.1 parser for Rust (crates.io). There is a request smuggling vulnerability in async-h1 before version 2.3.0. This vulnerability affects any webserver that uses async-h1 behind a reverse proxy, including all such Tide applications. If the server does not read the body of a request which is longer than some buffer length, async-h1 will attempt to read a subsequent request from the body content starting at that offset into the body. One way to exploit this vulnerability would be for an adversary to craft a request such that the body contains a request that would not be noticed by a reverse proxy, allowing it to forge forwarded/x-forwarded headers. If an application trusted the authenticity of these headers, it could be misled by the smuggled request. Another potential concern with this vulnerability is that if a reverse proxy is sending multiple http clients' requests along the same keep-alive connection, it would be possible for the smuggled request to specify a long content and capture another user's request in its body. This content could be captured in a post request to an endpoint that allows the content to be subsequently retrieved by the adversary. This has been addressed in async-h1 2.3.0 and previous versions have been yanked.
Weakness: CWE-444
Which versions are affected by CVE-2020-26281?
It affects 1 product.
Products include Rust-Lang Async-H1.
How do I fix CVE-2020-26281?
Upgrade to a fixed version.
Is CVE-2020-26281 being exploited?
There is no known exploitation of CVE-2020-26281 in the wild and no public exploit code.