CVE-2022-4203 — openssl-src
MEDIUMCVE-2022-4203 is a medium-severity (CVSS 4.9) Out-of-bounds Read vulnerability in openssl-src. A fix is available for openssl-src — see the affected versions and patch details below.
X.509 Name Constraints Read Buffer Overflow
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2022-4203.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2022-4203 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 378,156 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
openssl-srcReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects crates.io packages — download data is not available via public APIs for these ecosystems.
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | openssl-src | ≥ 300.0.0&&< 300.0.12 | 300.0.12cargo update -p openssl-src --precise 300.0.12 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for openssl-src, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update openssl-src to 300.0.12 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2022-4203 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2022-4203 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2022-4203. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
Red Hat Enterprise Linux 6, 7, and 8 ships OpenSSL 1.1.1 and 1.0.2 which do not contain the incorrect code, so those are not affected by this CVE. Similarly, the versions of `shim` as shipped with Red Hat Enterprise Linux 8 and 9 are not affected by this issue.
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat Enterprise Linux 9 | openssl-1:3.0.1-47.el9_1 | RHSA-2023:0946 |
| Red Hat Enterprise Linux 9.0 Extended Update Support | openssl-1:3.0.1-46.el9_0 | RHSA-2023:1199 |
Frequently Asked Questions
Is CVE-2022-4203 in your dependencies?
O3 Security finds CVE-2022-4203 across crates.io dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.