CVE-2021-43523
9.6 · CRITICALOverview
CVE-2021-43523 is a critical-severity vulnerability affecting uclibc uclibc. It was published on November 10, 2021 and has a CVSS 3.1 base score of 9.6 (CRITICAL).
This vulnerability has a CVSS 3.1 base score of 9.6, rated CRITICAL. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
Technical Description
In uClibc and uClibc-ng before 1.0.39, incorrect handling of special characters in domain names returned by DNS servers via gethostbyname, getaddrinfo, gethostbyaddr, and getnameinfo can lead to output of wrong hostnames (leading to domain hijacking) or injection into applications (leading to remote code execution, XSS, applications crashes, etc.). In other words, a validation step, which is expected in any stub resolver, does not occur.
Remediation
Check the references section for vendor advisories and patches from uclibc. Update uclibc to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| uclibc | uclibc | 0 | Affected |
| uclibc-ng_project | uclibc-ng | >= 0, < 1.0.39 | Affected |
References
Frequently Asked Questions
What is CVE-2021-43523?
CVE-2021-43523 is a critical-severity vulnerability affecting uclibc uclibc. It was published on November 10, 2021 and has a CVSS 3.1 base score of 9.6 (CRITICAL).
How severe is CVE-2021-43523?
This vulnerability has a CVSS 3.1 base score of 9.6, rated CRITICAL. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
How do I fix or remediate CVE-2021-43523?
Check the references section for vendor advisories and patches from uclibc. Update uclibc to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2021-43523?
CyberStrike's AI-powered security agents can automatically detect CVE-2021-43523 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
AI agents map your attack surface to find vulnerabilities like this one.
Automated penetration testing that runs continuously, not just quarterly.
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Browser-based exploitation validates findings with real proof-of-concept.
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