SB2021040116 - HTTP request smuggling in Netty

Description

This security bulletin contains information about 1 security vulnerability.

1) Inconsistent interpretation of HTTP requests (CVE-ID: CVE-2021-21409)

The vulnerability allows a remote attacker to preform HTTP request smuggling attacks.

The vulnerability exists due to improper validation of HTTP requests in io.netty:netty-codec-http2 in Netty, if the request only uses a single Http2HeaderFrame with the endStream set to to true. A remote attacker can send a specially crafted HTTP request to the server and smuggle arbitrary HTTP headers.

Successful exploitation of vulnerability may allow an attacker to poison HTTP cache and perform phishing attacks.

Remediation

Install update from vendor's website.

References

• https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-21295
• https://github.com/netty/netty/commit/b0fa4d5aab4215f3c22ce6123dd8dd5f38dc0432
• https://github.com/netty/netty/security/advisories/GHSA-f256-j965-7f32
• https://github.com/netty/netty/security/advisories/GHSA-wm47-8v5p-wjpj