CVE-2020-26281

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.

• CVE ID
• CVE-2020-26281

• Assigner
• security-advisories@github.com

• Vulnerability Status
• Analyzed

• Published Version
• 2020-12-21T22:15:13

• Last Modified Date
• 2021-02-16T17:16:16

• Version
• 2.0

• Vector String
• AV:N/AC:M/Au:N/C:P/I:P/A:N

• Access Vector
• NETWORK

• Access Compatibility
• MEDIUM

• Authentication
• NONE

• Confidentiality Impact
• PARTIAL

• Integrity Impact
• PARTIAL

• Availability Impact
• NONE

• Base Score
• 5.8

• Severity
• MEDIUM

• Exploitability Score
• 8.6

• Impact Score
• 4.9

• Version
• 3.1

• Vector String
• CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:H/A:N

• Attack Vector
• NETWORK

• Attack Compatibility
• HIGH

• Privileges Required
• NONE

• User Interaction
• NONE

• Scope
• CHANGED

• Confidentiality Impact
• LOW

• Availability Impact
• NONE

• Base Score
• 7.5

• Base Severity
• HIGH

• Exploitability Score
• 2.2

• Impact Score
• 4.7