Vulnerability 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.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Varnish-Cache | Varnish Cache | >= 6.0.0, < 6.0.8 |
| Varnish-Software | Varnish Cache | >= 6.0.0, <= 6.0.5 |
| Varnish Cache Project | Varnish Cache | >= 5.0.0, <= 5.2.1 |
| Fedoraproject | Fedora | 33 |
| Debian | Debian Linux | 10.0 |
Related Weaknesses (CWE)
References
- https://docs.varnish-software.com/security/VSV00007/MitigationVendor Advisory
- https://github.com/varnishcache/varnish-cache/commit/82b0a629f60136e76112c6f2c63PatchThird Party Advisory
- https://github.com/varnishcache/varnish-cache/commit/9be22198e258d0e7a5c41f42917PatchThird Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro
- https://varnish-cache.org/security/VSV00007.htmlMitigationVendor Advisory
- https://www.debian.org/security/2022/dsa-5088Third Party Advisory
- https://docs.varnish-software.com/security/VSV00007/MitigationVendor Advisory
- https://github.com/varnishcache/varnish-cache/commit/82b0a629f60136e76112c6f2c63PatchThird Party Advisory
- https://github.com/varnishcache/varnish-cache/commit/9be22198e258d0e7a5c41f42917PatchThird Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro
- https://varnish-cache.org/security/VSV00007.htmlMitigationVendor Advisory
- https://www.debian.org/security/2022/dsa-5088Third Party Advisory
FAQ
What is CVE-2021-36740?
CVE-2021-36740 is a vulnerability with a CVSS score of 6.5 (MEDIUM). 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, an...
How severe is CVE-2021-36740?
CVE-2021-36740 has been rated MEDIUM with a CVSS base score of 6.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2021-36740?
Check the references section above for vendor advisories and patch information. Affected products include: Varnish-Cache Varnish Cache, Varnish-Software Varnish Cache, Varnish Cache Project Varnish Cache, Fedoraproject Fedora, Debian Debian Linux.