CVE-2021-36740

MEDIUM

Varnish-cache Varnish Cache < 6.0.8 - HTTP Request Smuggling

Title source: rule

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.

References (7)

[Mitigation, Vendor Advisory] https://varnish-cache.org/security/VSV00007.html

[Mitigation, Vendor Advisory] https://docs.varnish-software.com/security/VSV00007/

[Patch, Third Party Advisory] https://github.com/varnishcache/varnish-cache/commit/9be22198e258d0e7a5c41f4291792214a29405cf

[Patch, Third Party Advisory] https://github.com/varnishcache/varnish-cache/commit/82b0a629f60136e76112c6f2c6372cce77b683be

[Mailing List, Third Party Advisory] https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZHBNLDEOTGYRIEQZBWV7F6VPYS4O2AAK/

[Mailing List, Third Party Advisory] https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/THV2DQA2GS65HUCKK4KSD2XLN3AAQ2V5/

[Third Party Advisory] https://www.debian.org/security/2022/dsa-5088

Scores

CVSS v3 6.5

EPSS 0.0071

EPSS Percentile 72.3%

Attack Vector NETWORK

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

Details

CWE

CWE-444

Status published

Products (9)

debian/debian_linux 10.0

debian/debian_linux 11.0

fedoraproject/fedora 33

fedoraproject/fedora 34

varnish-cache/varnish_cache 6.0.8 r1 (2 CPE variants)

varnish-cache/varnish_cache 6.0.0 - 6.0.8

varnish-software/varnish_cache 6.0.0 - 6.0.5

varnish-software/varnish_cache 6.0.0 - 6.0.7

varnish_cache_project/varnish_cache 5.0.0 - 5.2.1

Published Jul 14, 2021

Tracked Since Feb 18, 2026