Vulnerability record · CVE-2022-3602 · published 1 November 2022
CVE-2022-3602: OpenSSL X.509 name constraint check buffer overrun
OOpenssl · Openssl
OpenSSL 3.0.0 through 3.0.6 contains an out-of-bounds write (CWE-787) in X.509 certificate verification, specifically in name constraint checking. A crafted certificate can overflow four attacker-controlled bytes on the stack after chain signature verification, causing a crash or potentially remote code execution. The flaw was pre-announced as critical but downgraded to high after analysis of stack overflow protections and stack layout variability.
Description
A 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. An attacker can craft a malicious email address to overflow four attacker-controlled bytes on the stack. This buffer overflow could result in a crash (causing a denial of service) or potentially remote code execution. Many platforms implement stack overflow protections which would mitigate against the risk of remote code execution. The risk may be further mitigated based on stack layout for any given platform/compiler. Pre-announcements of CVE-2022-3602 described this issue as CRITICAL. Further analysis based on some of the mitigating factors described above have led this to be downgraded to HIGH. Users are still encouraged to upgrade to a new version as soon as possible. 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. Fixed in OpenSSL 3.0.7 (Affected 3.0.0,3.0.1,3.0.2,3.0.3,3.0.4,3.0.5,3.0.6).
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Automated analysis
high priorityNetwork-reachable, no authentication or interaction required, high CVSS (7.5) and very high EPSS, though RCE is conditional on platform stack protections and stack layout.
What it is
OpenSSL 3.0.0 through 3.0.6 contains an out-of-bounds write (CWE-787) in X.509 certificate verification, specifically in name constraint checking. A crafted certificate can overflow four attacker-controlled bytes on the stack after chain signature verification, causing a crash or potentially remote code execution. The flaw was pre-announced as critical but downgraded to high after analysis of stack overflow protections and stack layout variability.
Impact
An attacker can crash the process, causing denial of service, or potentially achieve remote code execution depending on platform stack protections and layout. The CVSS vector rates confidentiality and integrity impact as none and availability impact as high.
Attack surface
Reachable over the network with no authentication or user interaction (AV:N/AC:L/PR:N/UI:N). In a TLS client it triggers when connecting to a malicious server; in a TLS server it triggers when the server requests client authentication and a malicious client connects. Exploitation requires a CA to have signed the malicious certificate or the application to continue verification despite failure to build a path to a trusted issuer.
Exploitation
Not listed in CISA KEV and no ransomware groups are documented using it. EPSS is very high (0.9077 probability, 0.99799 percentile), and references are advisory and mailing-list entries only, with no public exploit tag in the record.
What to do
- Upgrade OpenSSL to 3.0.7 or later; affected versions are 3.0.0 through 3.0.6.
- Update dependent products listed in the record (Fedora, NetApp Clustered Data ONTAP, Node.js) to builds that bundle the fixed OpenSSL.
- Where immediate upgrade is not possible, disable or avoid client certificate authentication on TLS servers and restrict outbound TLS connections to trusted endpoints.
- Ensure stack overflow protections (stack canaries, ASLR, non-executable stack) are enabled to reduce RCE risk.
- Monitor OpenSSL security advisories and vendor bulletins for updated guidance.
Detection
- Search hosts and container images for OpenSSL versions 3.0.0 through 3.0.6 and for applications statically linking those versions.
- Monitor TLS server and client processes for unexpected crashes or restarts that coincide with certificate verification.
- Review TLS logs for certificate chain verification failures followed by continued processing, which the flaw requires.
- Track connections to untrusted or newly observed TLS endpoints, especially where client authentication is requested.
This assessment is produced automatically and is not human-reviewed. Verify against the vendor advisory before acting on it.
Affected products
4 vulnerable configurations from NVD's CPE data, grouped by vendor and product.
References
Track CVE-2022-3602 inside VULONE
Watch it alongside the ransomware crews, C2 infrastructure and forum chatter that reference it, query it through the API and pull it into your SIEM over TAXII.
Related vulnerabilities
Same products first, then exploited flaws of the same weakness class.
Source: NIST National Vulnerability Database (record CVE-2022-3602), CISA KEV, FIRST EPSS (scores of 2026-09-24). This page is refreshed as NVD updates the record.
