CVE-2022-4203: X.509 Name Constraints Read Buffer Overflow

Vulnerability summary

CVE-2022-4203 is a medium (CVSS 4.9) Out-of-bounds Read vulnerability in openssl. EPSS estimates a 1.39% chance of exploitation in the next 30 days, higher than 72.2% of scored vulnerabilities.

Timeline

1. 24-02-2023
   PublishedVulnerability first disclosed.
2. 04-11-2025
   Last modifiedVulnerability information updated.

Description

A read buffer overrun can be triggered in X.509 certificate verification, specifically in name constraint checking. Note that this occurs after certificate chain signature verification and requires either a CA to have signed the malicious certificate or for the application to continue certificate verification despite failure to construct a path to a trusted issuer. The read buffer overrun might result in a crash which could lead to a denial of service attack. In theory it could also result in the disclosure of private memory contents (such as private keys, or sensitive plaintext) although we are not aware of any working exploit leading to memory contents disclosure as of the time of release of this advisory. In a TLS client, this can be triggered by connecting to a malicious server. In a TLS server, this can be triggered if the server requests client authentication and a malicious client connects.

• CWE-125Out-of-bounds ReadThe product reads data past the end, or before the beginning, of the intended buffer.