Login Request a demo
Medium severity · published Jul 14, 2021
CVE-2021-36740
Varnish Cache, with HTTP/2 enabled, allows request smuggling and VCL authorization bypass via a large Content-Length header for a POST request
6.5
CVSS
1.6%
EPSS
No
On KEV
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 vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
Low
Integrity
Low
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)1.6% · higher than 76% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
DL
Debian Linux · Debian
10.0; 11.0 · source: NVD
FE
Fedora · Fedoraproject
33; 34 · source: NVD
VC
Varnish Cache · Varnish-cache
6.0.0 before 6.0.8; 6.0.8; 6.0.8 · source: NVD
Affected product
DL
Debian Linux
Debian
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-36740
CVE.org
https://www.cve.org/CVERecord?id=CVE-2021-36740
Mitigation
https://docs.varnish-software.com/security/VSV00007/
Patch
https://github.com/varnishcache/varnish-cache/commit/82b0a629f60136e76112c6f2c6372cce77b683be
Patch
https://github.com/varnishcache/varnish-cache/commit/9be22198e258d0e7a5c41f4291792214a29405cf
lists.fedoraproject.org
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/THV2DQA2GS65HUCKK4KSD2XLN3AAQ2V5/
lists.fedoraproject.org
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZHBNLDEOTGYRIEQZBWV7F6VPYS4O2AAK/
Mitigation
https://varnish-cache.org/security/VSV00007.html
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