High severity · published Aug 16, 2021
CVE-2021-33193
A crafted method sent through HTTP/2 will bypass validation and be forwarded by mod_proxy, which can lead to request splitting or cache poisoning
7.5
CVSS
46.2%
EPSS
No
On KEV
Description
A crafted method sent through HTTP/2 will bypass validation and be forwarded by mod_proxy, which can lead to request splitting or cache poisoning. This issue affects Apache HTTP Server 2.4.17 to 2.4.48.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
High
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)46.2% · higher than 99% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
HS
HTTP Server · Apache
2.4.17 before 2.4.49 · source: NVD
DL
Debian Linux · Debian
10.0 · source: NVD
FE
Fedora · Fedoraproject
34; 35 · source: NVD
SB
Secure Backup · Oracle
before 18.1.0.1.0 · source: NVD
TE
Tenable.sc · Tenable
through 5.19.1 · source: NVD
ZS
Zfs Storage Appliance Kit · Oracle
8.8 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-33193
CVE.org
https://www.cve.org/CVERecord?id=CVE-2021-33193
Patch
https://github.com/apache/httpd/commit/ecebcc035ccd8d0e2984fe41420d9e944f456b3c.patch
Patch
https://lists.apache.org/thread.html/re4162adc051c1a0a79e7a24093f3776373e8733abaff57253fef341d%40%3Ccvs.httpd.apache.org%3E
Patch
https://lists.apache.org/thread.html/ree7519d71415ecdd170ff1889cab552d71758d2ba2904a17ded21a70%40%3Ccvs.httpd.apache.org%3E
Mailing List
https://lists.debian.org/debian-lts-announce/2023/03/msg00002.html
Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/DSM6UWQICBJ2TU727RENU3HBKEAFLT6T/
Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/EUVJVRJRBW5QVX4OY3NOHZDQ3B3YOTSG/
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