CVE-2023-53159 is a medium-severity (CVSS 4.5) CWE-126 vulnerability in openssl. A fix is available for openssl — see the affected versions and patch details below.
`openssl` `X509VerifyParamRef::set_host` buffer over-read
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-2023-53159.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
opensslReal-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
When this function was passed an empty string, openssl would attempt to call strlen on it, reading arbitrary memory until it reached a NUL byte.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | openssl | ≥ 0.10.0&&< 0.10.55 | 0.10.55cargo update -p openssl --precise 0.10.55 |
Affected Products
opensslsfacklerDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for openssl, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update openssl to 0.10.55 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-53159 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.
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.
The assigned Moderate severity is based on the fact that while the vulnerability can be triggered without authentication, it requires a specific, less common user interaction (providing an empty string for a hostname). The direct impact is limited to information disclosure and does not lead to arbitrary code execution…
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.Source: Red Hat security advisory for CVE-2023-53159 (CC BY 4.0)
Frequently Asked Questions
Is CVE-2023-53159 in your dependencies?
Find it across crates.io, including transitive dependencies.