Apache Http Server CVEs.
Published CVEs affecting Apache Http Server, ranked by exploit odds.
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CVE-2011-3368
The mod_proxy module in the Apache HTTP Server 1.3.x through 1.3.42, 2.0.x through 2.0.64, and 2.2.x through 2.2.21 does not properly interact with use of (1) RewriteRule and (2) ProxyPassMatch pattern matches for configuration of a reverse proxy, which allows remote attackers to send requests to intranet servers via a malformed URI containing an initial @ (at sign) character.
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CVE-2022-30522
If Apache HTTP Server 2.4.53 is configured to do transformations with mod_sed in contexts where the input to mod_sed may be very large, mod_sed may make excessively large memory allocations and trigger an abort.
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CVE-2023-25690
Some mod_proxy configurations on Apache HTTP Server versions 2.4.0 through 2.4.55 allow a HTTP Request Smuggling attack. Configurations are affected when mod_proxy is enabled along with some form of RewriteRule or ProxyPassMatch in which a non-specific pattern matches some portion of the user-supplied request-target (URL) data and is then re-inserted into the proxied request-target using variable substitution. For example, something like: RewriteEngine on RewriteRule "^/here/(.*)" "http://example.com:8080/elsewhere?$1"; [P] ProxyPassReverse /here/ http://example.com:8080/ Request splitting/smuggling could result in bypass of access controls in the proxy server, proxying unintended URLs to existing origin servers, and cache poisoning. Users are recommended to update to at least version 2.4.56 of Apache HTTP Server.
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CVE-2012-0053
protocol.c in the Apache HTTP Server 2.2.x through 2.2.21 does not properly restrict header information during construction of Bad Request (aka 400) error documents, which allows remote attackers to obtain the values of HTTPOnly cookies via vectors involving a (1) long or (2) malformed header in conjunction with crafted web script.
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CVE-2015-3183
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 chunk-extension characters in modules/http/http_filters.c.
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CVE-2019-10098
In Apache HTTP server 2.4.0 to 2.4.39, Redirects configured with mod_rewrite that were intended to be self-referential might be fooled by encoded newlines and redirect instead to an unexpected URL within the request URL.
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CVE-2019-17567
Apache HTTP Server versions 2.4.6 to 2.4.46 mod_proxy_wstunnel configured on an URL that is not necessarily Upgraded by the origin server was tunneling the whole connection regardless, thus allowing for subsequent requests on the same connection to pass through with no HTTP validation, authentication or authorization possibly configured.
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CVE-2011-4317
The mod_proxy module in the Apache HTTP Server 1.3.x through 1.3.42, 2.0.x through 2.0.64, and 2.2.x through 2.2.21, when the Revision 1179239 patch is in place, does not properly interact with use of (1) RewriteRule and (2) ProxyPassMatch pattern matches for configuration of a reverse proxy, which allows remote attackers to send requests to intranet servers via a malformed URI containing an @ (at sign) character and a : (colon) character in invalid positions. NOTE: this vulnerability exists because of an incomplete fix for CVE-2011-3368.
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CVE-2002-0654
Apache 2.0 through 2.0.39 on Windows, OS2, and Netware allows remote attackers to determine the full pathname of the server via (1) a request for a .var file, which leaks the pathname in the resulting error message, or (2) via an error message that occurs when a script (child process) cannot be invoked.
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CVE-2013-5704
The mod_headers module in the Apache HTTP Server 2.2.22 allows remote attackers to bypass "RequestHeader unset" directives by placing a header in the trailer portion of data sent with chunked transfer coding. NOTE: the vendor states "this is not a security issue in httpd as such."
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CVE-2017-7668
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 segmentation fault, or to force ap_find_token() to return an incorrect value.
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CVE-2020-1927
In Apache HTTP Server 2.4.0 to 2.4.41, redirects configured with mod_rewrite that were intended to be self-referential might be fooled by encoded newlines and redirect instead to an an unexpected URL within the request URL.
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CVE-2016-5387
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 traffic to an arbitrary proxy server via a crafted Proxy header in an HTTP request, aka an "httpoxy" issue. NOTE: the vendor states "This mitigation has been assigned the identifier CVE-2016-5387"; in other words, this is not a CVE ID for a vulnerability.
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CVE-2022-37436
Prior to Apache HTTP Server 2.4.55, a malicious backend can cause the response headers to be truncated early, resulting in some headers being incorporated into the response body. If the later headers have any security purpose, they will not be interpreted by the client.
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CVE-2021-30641
Apache HTTP Server versions 2.4.39 to 2.4.46 Unexpected matching behavior with 'MergeSlashes OFF'
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CVE-2011-3639
The mod_proxy module in the Apache HTTP Server 2.0.x through 2.0.64 and 2.2.x before 2.2.18, when the Revision 1179239 patch is in place, does not properly interact with use of (1) RewriteRule and (2) ProxyPassMatch pattern matches for configuration of a reverse proxy, which allows remote attackers to send requests to intranet servers by using the HTTP/0.9 protocol with a malformed URI containing an initial @ (at sign) character. NOTE: this vulnerability exists because of an incomplete fix for CVE-2011-3368.
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CVE-2005-2700
ssl_engine_kernel.c in mod_ssl before 2.8.24, when using "SSLVerifyClient optional" in the global virtual host configuration, does not properly enforce "SSLVerifyClient require" in a per-location context, which allows remote attackers to bypass intended access restrictions.
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CVE-2022-22720
Apache HTTP Server 2.4.52 and earlier fails to close inbound connection when errors are encountered discarding the request body, exposing the server to HTTP Request Smuggling
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CVE-2024-38473
Encoding problem in mod_proxy in Apache HTTP Server 2.4.59 and earlier allows request URLs with incorrect encoding to be sent to backend services, potentially bypassing authentication via crafted requests. Users are recommended to upgrade to version 2.4.60, which fixes this issue.
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CVE-2022-26377
Inconsistent Interpretation of HTTP Requests ('HTTP Request Smuggling') vulnerability in mod_proxy_ajp of Apache HTTP Server allows an attacker to smuggle requests to the AJP server it forwards requests to. This issue affects Apache HTTP Server Apache HTTP Server 2.4 version 2.4.53 and prior versions.
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CVE-2005-2088
The Apache HTTP server before 1.3.34, and 2.0.x before 2.0.55, when acting as an HTTP proxy, allows remote attackers to poison the web cache, bypass web application firewall protection, and conduct XSS attacks via an HTTP request with both a "Transfer-Encoding: chunked" header and a Content-Length header, which causes Apache to incorrectly handle and forward the body of the request in a way that causes the receiving server to process it as a separate HTTP request, aka "HTTP Request Smuggling."
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CVE-2018-17199
In Apache HTTP Server 2.4 release 2.4.37 and prior, mod_session checks the session expiry time before decoding the session. This causes session expiry time to be ignored for mod_session_cookie sessions since the expiry time is loaded when the session is decoded.
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CVE-2016-4975
Possible CRLF injection allowing HTTP response splitting attacks for sites which use mod_userdir. This issue was mitigated by changes made in 2.4.25 and 2.2.32 which prohibit CR or LF injection into the "Location" or other outbound header key or value. Fixed in Apache HTTP Server 2.4.25 (Affected 2.4.1-2.4.23). Fixed in Apache HTTP Server 2.2.32 (Affected 2.2.0-2.2.31).
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CVE-2003-0083
Apache 1.3 before 1.3.25 and Apache 2.0 before version 2.0.46 does not filter terminal escape sequences from its access logs, which could make it easier for attackers to insert those sequences into terminal emulators containing vulnerabilities related to escape sequences, a different vulnerability than CVE-2003-0020.
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CVE-2008-0456
CRLF injection vulnerability in the mod_negotiation module in the Apache HTTP Server 2.2.6 and earlier in the 2.2.x series, 2.0.61 and earlier in the 2.0.x series, and 1.3.39 and earlier in the 1.3.x series allows remote authenticated users to inject arbitrary HTTP headers and conduct HTTP response splitting attacks by uploading a file with a multi-line name containing HTTP header sequences and a file extension, which leads to injection within a (1) "406 Not Acceptable" or (2) "300 Multiple Choices" HTTP response when the extension is omitted in a request for the file.
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CVE-2019-0220
A vulnerability was found in Apache HTTP Server 2.4.0 to 2.4.38. When the path component of a request URL contains multiple consecutive slashes ('/'), directives such as LocationMatch and RewriteRule must account for duplicates in regular expressions while other aspects of the servers processing will implicitly collapse them.
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CVE-2003-0020
Apache does not filter terminal escape sequences from its error logs, which could make it easier for attackers to insert those sequences into terminal emulators containing vulnerabilities related to escape sequences.
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CVE-2004-0885
The mod_ssl module in Apache 2.0.35 through 2.0.52, when using the "SSLCipherSuite" directive in directory or location context, allows remote clients to bypass intended restrictions by using any cipher suite that is allowed by the virtual host configuration.
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CVE-2002-1156
Apache 2.0.42 allows remote attackers to view the source code of a CGI script via a POST request to a directory with both WebDAV and CGI enabled.
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CVE-2013-2249
mod_session_dbd.c in the mod_session_dbd module in the Apache HTTP Server before 2.4.5 proceeds with save operations for a session without considering the dirty flag and the requirement for a new session ID, which has unspecified impact and remote attack vectors.
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CVE-2009-3095
The mod_proxy_ftp module in the Apache HTTP Server allows remote attackers to bypass intended access restrictions and send arbitrary commands to an FTP server via vectors related to the embedding of these commands in the Authorization HTTP header, as demonstrated by a certain module in VulnDisco Pack Professional 8.11.
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CVE-2016-8743
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 interacts with back-end application servers, either through mod_proxy or using conventional CGI mechanisms, and may result in request smuggling, response splitting and cache pollution.
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CVE-2002-1592
The ap_log_rerror function in Apache 2.0 through 2.035, when a CGI application encounters an error, sends error messages to the client that include the full path for the server, which allows remote attackers to obtain sensitive information.
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CVE-2003-0789
mod_cgid in Apache before 2.0.48, when using a threaded MPM, does not properly handle CGI redirect paths, which could cause Apache to send the output of a CGI program to the wrong client.
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CVE-2001-0730
split-logfile in Apache 1.3.20 allows remote attackers to overwrite arbitrary files that end in the .log extension via an HTTP request with a / (slash) in the Host: header.
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CVE-2003-0993
mod_access in Apache 1.3 before 1.3.30, when running big-endian 64-bit platforms, does not properly parse Allow/Deny rules using IP addresses without a netmask, which could allow remote attackers to bypass intended access restrictions.
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CVE-2018-1283
In Apache httpd 2.4.0 to 2.4.29, when mod_session is configured to forward its session data to CGI applications (SessionEnv on, not the default), a remote user may influence their content by using a "Session" header. This comes from the "HTTP_SESSION" variable name used by mod_session to forward its data to CGIs, since the prefix "HTTP_" is also used by the Apache HTTP Server to pass HTTP header fields, per CGI specifications.
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CVE-2001-0766
Apache on MacOS X Client 10.0.3 with the HFS+ file system allows remote attackers to bypass access restrictions via a URL that contains some characters whose case is not matched by Apache's filters.
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CVE-2001-1449
The default installation of Apache before 1.3.19 on Mandrake Linux 7.1 through 8.0 and Linux Corporate Server 1.0.1 allows remote attackers to list the directory index of arbitrary web directories.
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CVE-2004-0811
Unknown vulnerability in Apache 2.0.51 prevents "the merging of the Satisfy directive," which could allow attackers to obtain access to restricted resources contrary to the specified authentication configuration.
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CVE-2004-1082
mod_digest_apple for Apache 1.3.31 and 1.3.32 on Mac OS X Server does not properly verify the nonce of a client response, which allows remote attackers to replay credentials.
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CVE-2002-0240
PHP, when installed with Apache and configured to search for index.php as a default web page, allows remote attackers to obtain the full pathname of the server via the HTTP OPTIONS method, which reveals the pathname in the resulting error message.
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CVE-2002-0249
PHP for Windows, when installed on Apache 2.0.28 beta as a standalone CGI module, allows remote attackers to obtain the physical path of the php.exe via a request with malformed arguments such as /123, which leaks the pathname in the error message.
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CVE-2020-11985
IP address spoofing when proxying using mod_remoteip and mod_rewrite For configurations using proxying with mod_remoteip and certain mod_rewrite rules, an attacker could spoof their IP address for logging and PHP scripts. Note this issue was fixed in Apache HTTP Server 2.4.24 but was retrospectively allocated a low severity CVE in 2020.
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CVE-2003-0017
Apache 2.0 before 2.0.44 on Windows platforms allows remote attackers to obtain certain files via an HTTP request that ends in certain illegal characters such as ">", which causes a different filename to be processed and served.
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CVE-2007-1862
The recall_headers function in mod_mem_cache in Apache 2.2.4 does not properly copy all levels of header data, which can cause Apache to return HTTP headers containing previously used data, which could be used by remote attackers to obtain potentially sensitive information.
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CVE-2002-2103
Apache before 1.3.24, when writing to the log file, records a spoofed hostname from the reverse lookup of an IP address, even when a double-reverse lookup fails, which allows remote attackers to hide the original source of activities.
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CVE-2002-2012
Unknown vulnerability in Apache 1.3.19 running on HP Secure OS for Linux 1.0 allows remote attackers to cause "unexpected results" via an HTTP request.
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CVE-2003-0192
Apache 2 before 2.0.47, and certain versions of mod_ssl for Apache 1.3, do not properly handle "certain sequences of per-directory renegotiations and the SSLCipherSuite directive being used to upgrade from a weak ciphersuite to a strong one," which could cause Apache to use the weak ciphersuite.
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CVE-2003-0987
mod_digest for Apache before 1.3.31 does not properly verify the nonce of a client response by using a AuthNonce secret.
All CVEs affecting Apache Http Server that appear in CVE.org and NVD, sorted by how likely they are to be exploited (EPSS), with fix status and timeline.