Summary
James Kettle discovered that the Apache HTTP Server HTTP/2 module
incorrectly handled certain crafted methods. A remote attacker could
possibly use this issue to perform request splitting or cache poisoning
attacks. (CVE-2021-33193)
It was discovered that the Apache HTTP Server incorrectly handled certain
malformed requests. A remote attacker could possibly use this issue to
cause the server to crash, resulting in a denial of service.
(CVE-2021-34798)
Li Zhi Xin discovered that the Apache mod_proxy_uwsgi module incorrectly
handled certain request uri-paths. A remote attacker could possibly use
this issue to cause the server to crash, resulting in a denial of service.
This issue only affected Ubuntu 20.04 LTS and Ubuntu 21.04.
(CVE-2021-36160)
It was discovered that the Apache HTTP Server incorrectly handled escaping
quotes. If the server was configured with third-party modules, a remote
attacker could use this issue to cause the server to crash, resulting in a
denial of service, or possibly execute arbitrary code. (CVE-2021-39275)
It was discovered that the Apache mod_proxy module incorrectly handled
certain request uri-paths. A remote attacker could possibly use this issue
to cause the server to forward requests to arbitrary origin servers.
(CVE-2021-40438)
Fixed packages 2
| Release | Package | Fixed in |
|---|---|---|
| Ubuntu · 18.04 LTS 18.04:LTS | apache2 | 2.4.29-1ubuntu4.17 |
| Ubuntu · 20.04 LTS 20.04:LTS | apache2 | 2.4.41-4ubuntu3.5 |
Vulnerabilities 5
-
Critical 9.0
mod_proxy SSRF
A crafted request uri-path can cause mod_proxy to forward the request to an origin server choosen by the remote user. This issue affects Apache HTTP Server 2.4.48 and earlier.
KEV Dec 1, 2021 -
Unscored —CVE-2021-33193 EPSS 46%
Request splitting via HTTP/2 method injection and mod_proxy
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.
-
Unscored —CVE-2021-34798 EPSS 65%
NULL pointer dereference in httpd core
Malformed requests may cause the server to dereference a NULL pointer. This issue affects Apache HTTP Server 2.4.48 and earlier.
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Unscored —CVE-2021-36160 EPSS 64%
mod_proxy_uwsgi out of bound read
A carefully crafted request uri-path can cause mod_proxy_uwsgi to read above the allocated memory and crash (DoS). This issue affects Apache HTTP Server versions 2.4.30 to 2.4.48 (inclusive).
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Unscored —CVE-2021-39275 EPSS 39%
ap_escape_quotes buffer overflow
ap_escape_quotes() may write beyond the end of a buffer when given malicious input. No included modules pass untrusted data to these functions, but third-party / external modules may. This issue affects Apache HTTP Server 2.4.48 and earlier.