Apache httpd allows remote attackers to read secret data from process memory if the Limit directive can be set in a user's .htaccess file, or if httpd.conf has certain misconfigurations, aka Optionsbleed. This affects the Apache HTTP Server through 2.2.34 and 2.4.x through 2.4.27...
Product
Apache HTTP Server vulnerabilities
352 published CVES affecting Apache HTTP Server, from public sources (CVE.org, NVD, CISA KEV, FIRST EPSS, OSV).
- Total
- 352
- Critical
- 31
- High
- 131
- Medium
- 175
- Low
- 14
- Unscored
- 1
- CISA KEV
- 5
Latest Apache HTTP Server CVEs
Newest publication first · page 7 of 15
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HighCVSS 7.5 EPSS 94.7% Public exploit
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HighCVSS 7.5 EPSS 13.3%
Apache HTTP Server, in all releases prior to 2.2.32 and 2.4.25, was liberal in the whitespace accepted from requests and sent in response lines and headers. Accepting these different behaviors represented a security concern when httpd participates in any chain of proxies or inter...
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HighCVSS 7.5 EPSS 21.0%
In Apache HTTP Server versions 2.4.0 to 2.4.23, malicious input to mod_auth_digest can cause the server to crash, and each instance continues to crash even for subsequently valid requests.
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HighCVSS 7.5 EPSS 49.0%
In Apache HTTP Server versions 2.4.0 to 2.4.23, mod_session_crypto was encrypting its data/cookie using the configured ciphers with possibly either CBC or ECB modes of operation (AES256-CBC by default), hence no selectable or builtin authenticated encryption. This made it vulnera...
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HighCVSS 7.5 EPSS 53.9%
A maliciously constructed HTTP/2 request could cause mod_http2 in Apache HTTP Server 2.4.24, 2.4.25 to dereference a NULL pointer and crash the server process.
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HighCVSS 7.5 EPSS 9.5%
When under stress, closing many connections, the HTTP/2 handling code in Apache httpd 2.4.26 would sometimes access memory after it has been freed, resulting in potentially erratic behaviour.
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CriticalCVSS 9.1 EPSS 56.8%
In Apache httpd before 2.2.34 and 2.4.x before 2.4.27, the value placeholder in [Proxy-]Authorization headers of type 'Digest' was not initialized or reset before or between successive key=value assignments by mod_auth_digest. Providing an initial key with no '=' assignment could...
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CriticalCVSS 9.8 EPSS 39.3%
In Apache httpd 2.2.x before 2.2.33 and 2.4.x before 2.4.26, mod_mime can read one byte past the end of a buffer when sending a malicious Content-Type response header.
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HighCVSS 7.5 EPSS 57.5%
The HTTP strict parsing changes added in Apache httpd 2.2.32 and 2.4.24 introduced a bug in token list parsing, which allows ap_find_token() to search past the end of its input string. By maliciously crafting a sequence of request headers, an attacker may be able to cause a segme...
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CriticalCVSS 9.8 EPSS 20.0%
In Apache httpd 2.2.x before 2.2.33 and 2.4.x before 2.4.26, mod_ssl may dereference a NULL pointer when third-party modules call ap_hook_process_connection() during an HTTP request to an HTTPS port.
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CriticalCVSS 9.8 EPSS 20.2%
In Apache httpd 2.2.x before 2.2.33 and 2.4.x before 2.4.26, use of the ap_get_basic_auth_pw() by third-party modules outside of the authentication phase may lead to authentication requirements being bypassed.
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HighCVSS 7.5 EPSS 79.1%
The mod_http2 module in the Apache HTTP Server 2.4.17 through 2.4.23, when the Protocols configuration includes h2 or h2c, does not restrict request-header length, which allows remote attackers to cause a denial of service (memory consumption) via crafted CONTINUATION frames in a...
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HighCVSS 8.1 EPSS 55.7%
The Apache HTTP Server through 2.4.23 follows RFC 3875 section 4.1.18 and therefore does not protect applications from the presence of untrusted client data in the HTTP_PROXY environment variable, which might allow remote attackers to redirect an application's outbound HTTP traff...
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HighCVSS 7.5 EPSS 18.8%
The Apache HTTP Server 2.4.18 through 2.4.20, when mod_http2 and mod_ssl are enabled, does not properly recognize the "SSLVerifyClient require" directive for HTTP/2 request authorization, which allows remote attackers to bypass intended access restrictions by leveraging the abili...
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MediumCVSS 5.9 EPSS 15.9%
The Apache HTTP Server 2.4.17 and 2.4.18, when mod_http2 is enabled, does not limit the number of simultaneous stream workers for a single HTTP/2 connection, which allows remote attackers to cause a denial of service (stream-processing outage) via modified flow-control windows.
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MediumCVSS 5.0 EPSS 12.8%
The read_request_line function in server/protocol.c in the Apache HTTP Server 2.4.12 does not initialize the protocol structure member, which allows remote attackers to cause a denial of service (NULL pointer dereference and process crash) by sending a request that lacks a method...
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MediumCVSS 4.3 EPSS 16.3%
The ap_some_auth_required function in server/request.c in the Apache HTTP Server 2.4.x before 2.4.14 does not consider that a Require directive may be associated with an authorization setting rather than an authentication setting, which allows remote attackers to bypass intended...
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MediumCVSS 5.0 EPSS 74.4%
The chunked transfer coding implementation in the Apache HTTP Server before 2.4.14 does not properly parse chunk headers, which allows remote attackers to conduct HTTP request smuggling attacks via a crafted request, related to mishandling of large chunk-size values and invalid c...
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MediumCVSS 5.0 EPSS 16.9%
The lua_websocket_read function in lua_request.c in the mod_lua module in the Apache HTTP Server through 2.4.12 allows remote attackers to cause a denial of service (child-process crash) by sending a crafted WebSocket Ping frame after a Lua script has called the wsupgrade functio...
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MediumCVSS 4.3 EPSS 22.0%
mod_lua.c in the mod_lua module in the Apache HTTP Server 2.3.x and 2.4.x through 2.4.10 does not support an httpd configuration in which the same Lua authorization provider is used with different arguments within different contexts, which allows remote attackers to bypass intend...
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MediumCVSS 5.0 EPSS 10.8%
The handle_headers function in mod_proxy_fcgi.c in the mod_proxy_fcgi module in the Apache HTTP Server 2.4.10 allows remote FastCGI servers to cause a denial of service (buffer over-read and daemon crash) via long response headers.
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MediumCVSS 5.0 EPSS 13.5%
The cache_merge_headers_out function in modules/cache/cache_util.c in the mod_cache module in the Apache HTTP Server before 2.4.11 allows remote attackers to cause a denial of service (NULL pointer dereference and application crash) via an empty HTTP Content-Type header.
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MediumCVSS 5.0 EPSS 16.8%
Memory leak in the winnt_accept function in server/mpm/winnt/child.c in the WinNT MPM in the Apache HTTP Server 2.4.x before 2.4.10 on Windows, when the default AcceptFilter is enabled, allows remote attackers to cause a denial of service (memory consumption) via crafted requests...
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MediumCVSS 5.0 EPSS 44.7%
The mod_cgid module in the Apache HTTP Server before 2.4.10 does not have a timeout mechanism, which allows remote attackers to cause a denial of service (process hang) via a request to a CGI script that does not read from its stdin file descriptor.
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MediumCVSS 4.3 EPSS 37.3%
The deflate_in_filter function in mod_deflate.c in the mod_deflate module in the Apache HTTP Server before 2.4.10, when request body decompression is enabled, allows remote attackers to cause a denial of service (resource consumption) via crafted request data that decompresses to...
Sources: CVE.org, NVD, CISA KEV, FIRST EPSS, OSV and public exploit-reference metadata. Product matching comes from the published CVE records. A proof-of-concept means public code exists; it is not evidence of exploitation.