CVE-2021-43557
7.5 · HIGHOverview
CVE-2021-43557 is a high-severity vulnerability affecting apache apisix. It was published on November 22, 2021 and has a CVSS 3.1 base score of 7.5 (HIGH).
This vulnerability has a CVSS 3.1 base score of 7.5, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
Technical Description
The uri-block plugin in Apache APISIX before 2.10.2 uses $request_uri without verification. The $request_uri is the full original request URI without normalization. This makes it possible to construct a URI to bypass the block list on some occasions. For instance, when the block list contains "^/internal/", a URI like `//internal/` can be used to bypass it. Some other plugins also have the same issue. And it may affect the developer's custom plugin.
Remediation
Check the references section for vendor advisories and patches from apache. Update apisix 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 |
|---|---|---|---|
| apache | apisix | >= 0, < 2.10.2 | Affected |
References
Frequently Asked Questions
What is CVE-2021-43557?
CVE-2021-43557 is a high-severity vulnerability affecting apache apisix. It was published on November 22, 2021 and has a CVSS 3.1 base score of 7.5 (HIGH).
How severe is CVE-2021-43557?
This vulnerability has a CVSS 3.1 base score of 7.5, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
How do I fix or remediate CVE-2021-43557?
Check the references section for vendor advisories and patches from apache. Update apisix 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-2021-43557?
CyberStrike's AI-powered security agents can automatically detect CVE-2021-43557 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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