#VU45739 Input validation error in nim - CVE-2020-15694

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to insufficient validation of server responses in the standard library httpClient. A remote attacker can pass specially crafted input to the application and perform a denial of service (DoS) attack or force the application to perform unexpected actions as demonstrated by the  httpClient.get().contentLength() that does not raise any error if a malicious server provides a negative Content-Length.

Remediation

External links

• https://github.com/nim-lang/Nim/blob/dc5a40f3f39c6ea672e6dc6aca7f8118a69dda99/lib/pure/httpclient.nim#L241
• https://nim-lang.org/blog/2020/07/30/versions-126-and-108-released.html