Vulnerability in Apache Http_server
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. This issue affects Apache HTTP Server 2.4.17 to 2.4.48.
EPSS: 0.462 (98.7th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N.
Affected products
- Apache Http_server
- Apache Software Foundation Http Server — versions Apache HTTP Server 2.4 2.4.17 to 2.4.48
- Oracle Secure_backup
- Oracle Zfs_storage_appliance_kit — versions 8.8
- Tenable Tenable.sc
- Debian Debian_linux — versions 10.0
- Fedoraproject Fedora — versions 34, 35
Public proof-of-concept exploits
References
- security@apache.org (Exploit, Third Party Advisory)
- security@apache.org (Patch)
- security@apache.org (mailing-list, Patch)
- security@apache.org (mailing-list, Patch)
- security@apache.org (vendor-advisory, Third Party Advisory)
- security@apache.org (vendor-advisory, Third Party Advisory)
- security@apache.org (vendor-advisory, Third Party Advisory)
- security@apache.org (Patch, Third Party Advisory)
- security@apache.org (Third Party Advisory)
- security@apache.org (Third Party Advisory)
Frequently asked questions
- What is CVE-2021-33193?
- CVE-2021-33193 is a high-severity vulnerability in Apache Http_server. CVSS score: 7.5/10. Published 2021-08-16.
- How severe is CVE-2021-33193?
- High severity. CVSS v3 base score is 7.5 out of 10.
- Is CVE-2021-33193 known to be exploited?
- 14 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.