CVE-2021-39156
8.1 · HIGHOverview
CVE-2021-39156 is a high-severity vulnerability affecting istio istio. It was published on August 24, 2021 and has a CVSS 3.1 base score of 8.1 (HIGH).
This vulnerability has a CVSS 3.1 base score of 8.1, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
Technical Description
Istio is an open source platform for providing a uniform way to integrate microservices, manage traffic flow across microservices, enforce policies and aggregate telemetry data. Istio 1.11.0, 1.10.3 and below, and 1.9.7 and below contain a remotely exploitable vulnerability where an HTTP request with `#fragment` in the path may bypass Istio’s URI path based authorization policies. Patches are available in Istio 1.11.1, Istio 1.10.4 and Istio 1.9.8. As a work around a Lua filter may be written to normalize the path.
Remediation
Check the references section for vendor advisories and patches from istio. Update istio 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 |
|---|---|---|---|
| istio | istio | >= 0, < 1.9.8 | Affected |
Frequently Asked Questions
What is CVE-2021-39156?
CVE-2021-39156 is a high-severity vulnerability affecting istio istio. It was published on August 24, 2021 and has a CVSS 3.1 base score of 8.1 (HIGH).
How severe is CVE-2021-39156?
This vulnerability has a CVSS 3.1 base score of 8.1, 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-2021-39156?
Check the references section for vendor advisories and patches from istio. Update istio 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-2021-39156?
CyberStrike's AI-powered security agents can automatically detect CVE-2021-39156 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.
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