CVE-2020-26281
There is a request smuggling vulnerability in async-h1 before version 2.3.0.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (1.01%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 3.1
- 7.5 HIGHCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:H/A:N
- EPSS
- 1.01% probability · 61th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-444
- Affected
- rust-lang/async-h1
- Source
- security-advisories@github.com
References
- https://github.com/http-rs/async-h1/releases/tag/v2.3.0Release Notes, Third Party Advisory
- https://github.com/http-rs/async-h1/security/advisories/GHSA-4vr9-8cjf-vf9cThird Party Advisory
- https://github.com/http-rs/async-h1/releases/tag/v2.3.0Release Notes, Third Party Advisory
- https://github.com/http-rs/async-h1/security/advisories/GHSA-4vr9-8cjf-vf9cThird Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.