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Ubuntu Security Notice USN-5371-3
October 07, 2022

nginx vulnerability
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A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 16.04 ESM

Summary:

A security issue was fixed in nginx's lua module.

Software Description:
- nginx: small, powerful, scalable web/proxy server

Details:

USN-5371-1 and USN-5371-2 fixed several vulnerabilities in nginx.
This update provides the corresponding update for CVE-2020-11724
for Ubuntu 16.04 ESM.

Original advisory details:

 It was discovered that nginx Lua module mishandled certain inputs.
 An attacker could possibly use this issue to perform an HTTP Request
 Smuggling attack. This issue was fixed for Ubuntu 18.04 LTS and
 Ubuntu 20.04 LTS. (CVE-2020-11724)
 
 It was discovered that nginx Lua module mishandled certain inputs.
 An attacker could possibly use this issue to disclose sensitive
 information. This issue only affects Ubuntu 18.04 LTS and
 Ubuntu 20.04 LTS. (CVE-2020-36309)
 
 It was discovered that nginx mishandled the use of 
 compatible certificates among multiple encryption protocols. 
 If a remote attacker were able to intercept the communication, 
 this issue could be used to redirect traffic between subdomains.
 (CVE-2021-3618)

Update instructions:

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 16.04 ESM:
  nginx-core                      1.10.3-0ubuntu0.16.04.5+esm4
  nginx-extras                    1.10.3-0ubuntu0.16.04.5+esm4
  nginx-full                      1.10.3-0ubuntu0.16.04.5+esm4
  nginx-light                     1.10.3-0ubuntu0.16.04.5+esm4

In general, a standard system update will make all the necessary changes.

References:
  https://ubuntu.com/security/notices/USN-5371-3
  https://ubuntu.com/security/notices/USN-5371-1
  CVE-2020-11724