SB2022013115 - Red Hat Enterprise Linux 8 update for the nginx:1.20 module 

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Main Vulnerability Database SB2022013115

SB2022013115 - Red Hat Enterprise Linux 8 update for the nginx:1.20 module

Published: January 31, 2022 Updated: July 31, 2022

Security Bulletin ID SB2022013115
Severity
High
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Remote access
Highest impact Code execution

Breakdown by Severity

High 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 security vulnerability.


1) Off-by-one (CVE-ID: CVE-2021-23017)

The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to an off-by-one error within the ngx_resolver_copy() function when processing DNS responses. A remote attacker can trigger an off-by-one error, write a dot character (‘.’, 0x2E) out of bounds in a heap allocated buffer and execute arbitrary code on the system.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.

The vulnerability can be triggered by a DNS response in reply to a DNS request from nginx when the resolver primitive is configured. A specially crafted packet allows overwriting the least significant byte of next heap chunk metadata with 0x2E.


Remediation

Install update from vendor's website.

References