CVE-2021-36740
6.5 · MEDIUMOverview
CVE-2021-36740 is a medium-severity vulnerability affecting varnish-cache varnish_cache. It was published on July 14, 2021 and has a CVSS 3.1 base score of 6.5 (MEDIUM).
This vulnerability has a CVSS 3.1 base score of 6.5, rated MEDIUM. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
Technical Description
Varnish Cache, with HTTP/2 enabled, allows request smuggling and VCL authorization bypass via a large Content-Length header for a POST request. This affects Varnish Enterprise 6.0.x before 6.0.8r3, and Varnish Cache 5.x and 6.x before 6.5.2, 6.6.x before 6.6.1, and 6.0 LTS before 6.0.8.
Remediation
Check the references section for vendor advisories and patches from varnish-cache. Update varnish_cache 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 |
|---|---|---|---|
| varnish-cache | varnish_cache | >= 6.0.0, < 6.0.8 | Affected |
| varnish-software | varnish_cache | 6.0.0 | Affected |
| varnish_cache_project | varnish_cache | 5.0.0 | Affected |
References
Frequently Asked Questions
What is CVE-2021-36740?
CVE-2021-36740 is a medium-severity vulnerability affecting varnish-cache varnish_cache. It was published on July 14, 2021 and has a CVSS 3.1 base score of 6.5 (MEDIUM).
How severe is CVE-2021-36740?
This vulnerability has a CVSS 3.1 base score of 6.5, rated MEDIUM. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
How do I fix or remediate CVE-2021-36740?
Check the references section for vendor advisories and patches from varnish-cache. Update varnish_cache 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-2021-36740?
CyberStrike's AI-powered security agents can automatically detect CVE-2021-36740 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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