CVE-2021-36740

MediumCVSS 6.5/10Last modified Jun 17, 2026

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.

Metrics

CVSS 3.1 6.5/10CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Weakness enumeration

CWE-444

Affected software

Vendor	Product	Versions
n/a	n/a	n/a

References

https://docs.varnish-software.com/security/VSV00007/Mitigation, Vendor Advisory
https://github.com/varnishcache/varnish-cache/commit/82b0a629f60136e76112c6f2c6372cce77b683bePatch, Third Party Advisory
https://github.com/varnishcache/varnish-cache/commit/9be22198e258d0e7a5c41f4291792214a29405cfPatch, Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/THV2DQA2GS65HUCKK4KSD2XLN3AAQ2V5/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZHBNLDEOTGYRIEQZBWV7F6VPYS4O2AAK/
https://varnish-cache.org/security/VSV00007.htmlMitigation, Vendor Advisory
https://www.debian.org/security/2022/dsa-5088Third Party Advisory
https://docs.varnish-software.com/security/VSV00007/Mitigation, Vendor Advisory
https://github.com/varnishcache/varnish-cache/commit/82b0a629f60136e76112c6f2c6372cce77b683bePatch, Third Party Advisory
https://github.com/varnishcache/varnish-cache/commit/9be22198e258d0e7a5c41f4291792214a29405cfPatch, Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/THV2DQA2GS65HUCKK4KSD2XLN3AAQ2V5/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZHBNLDEOTGYRIEQZBWV7F6VPYS4O2AAK/
https://varnish-cache.org/security/VSV00007.htmlMitigation, Vendor Advisory
https://www.debian.org/security/2022/dsa-5088Third Party Advisory

Timeline

Published: Jul 14, 2021
Last modified: Jun 17, 2026
NVD status: Modified

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