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Critical severityNVD Advisory· Published Feb 24, 2023· Updated Nov 4, 2025

X.509 Name Constraints Read Buffer Overflow

CVE-2022-4203

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.

AI Insight

LLM-synthesized narrative grounded in this CVE's description and references.

A read buffer overrun in OpenSSL's X.509 name constraint checking can cause denial of service or potential memory disclosure.

Vulnerability

A read buffer overrun occurs in OpenSSL during X.509 certificate verification, specifically in name constraint checking. This happens after certificate chain signature verification and arises when parsing crafted name constraints, leading to reading beyond the allocated buffer boundaries. [1][2]

Exploitation

An attacker must either have a Certificate Authority sign a malicious certificate or the application must continue verification despite failing to construct a trusted path. In a TLS client, connecting to a malicious server can trigger the overrun. In a TLS server, it is triggered if the server requests client authentication and a malicious client connects. [1][2]

Impact

The overrun may crash the process, causing denial of service. Theoretically, it could disclose private memory contents such as private keys or sensitive plaintext, but no working exploit for memory disclosure has been reported as of the advisory. [1][2]

Mitigation

OpenSSL has released patches in versions 3.0.8, 1.1.1t, and 1.0.2zg. Users should upgrade to these versions. Gentoo also recommends updating to openssl-3.0.10. [1][4]

References
  1. https://www.openssl.org/news/secadv/20230207.txt
  2. NVD - CVE-2022-4203
  3. Multiple Vulnerabilities (GLSA 202402-08) — Gentoo security

AI Insight generated on May 20, 2026. Synthesized from this CVE's description and the cited reference URLs; citations are validated against the source bundle.

Affected packages

Versions sourced from the GitHub Security Advisory.

PackageAffected versionsPatched versions
openssl-srccrates.io
>= 300.0.0, < 300.0.12300.0.12

Affected products

43

Patches

0

No patches discovered yet.

Vulnerability mechanics

AI mechanics synthesis has not run for this CVE yet.

References

7

News mentions

0

No linked articles in our index yet.