Apache Software Foundation Apache Http Server vulnerabilities

CVE-2021-41773 [CRITICAL] CWE-22 CVE-2021-41773: A flaw was found in a change made to path normalization in Apache HTTP Server 2.4.49. An attacker co A flaw was found in a change made to path normalization in Apache HTTP Server 2.4.49. An attacker could use a path traversal attack to map URLs to files outside the directories configured by Alias-like directives. If files outside of these directories are not protected by the usual default configuration "require all denied", these requests can succ

CVE-2021-40438 [CRITICAL] CWE-918 CVE-2021-40438: A crafted request uri-path can cause mod_proxy to forward the request to an origin server choosen by 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.

CVE-2024-38475 [CRITICAL] CWE-116 CVE-2024-38475: Improper escaping of output in mod_rewrite in Apache HTTP Server 2.4.59 and earlier allows an attack Improper escaping of output in mod_rewrite in Apache HTTP Server 2.4.59 and earlier allows an attacker to map URLs to filesystem locations that are permitted to be served by the server but are not intentionally/directly reachable by any URL, resulting in code execution or source code disclosure. Substitutions in server context that use a backrefe

CVE-2023-25690 [CRITICAL] CWE-444 CVE-2023-25690: Some mod_proxy configurations on Apache HTTP Server versions 2.4.0 through 2.4.55 allow a HTTP Reque 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-ins

CVE-2017-9798 [HIGH] CWE-416 CVE-2017-9798: Apache httpd allows remote attackers to read secret data from process memory if the Limit directive 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. The attacker sends an unauthenticated OPTIONS HTTP request when attempting

CVE-2017-15715 [HIGH] CWE-20 CVE-2017-15715: In Apache httpd 2.4.0 to 2.4.29, the expression specified in <FilesMatch> could match '$' to a newli In Apache httpd 2.4.0 to 2.4.29, the expression specified in could match '$' to a newline character in a malicious filename, rather than matching only the end of the filename. This could be exploited in environments where uploads of some files are are externally blocked, but only by matching the trailing portion of the filename.

CVE-2016-0736 [HIGH] CWE-310 CVE-2016-0736: In Apache HTTP Server versions 2.4.0 to 2.4.23, mod_session_crypto was encrypting its data/cookie us 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 vulnerable to padding oracle attacks, particularly with CBC.

CVE-2018-8011 [HIGH] CWE-476 CVE-2018-8011: By specially crafting HTTP requests, the mod_md challenge handler would dereference a NULL pointer a By specially crafting HTTP requests, the mod_md challenge handler would dereference a NULL pointer and cause the child process to segfault. This could be used to DoS the server. Fixed in Apache HTTP Server 2.4.34 (Affected 2.4.33).

CVE-2017-9788 [CRITICAL] CWE-20 CVE-2017-9788: In Apache httpd before 2.2.34 and 2.4.x before 2.4.27, the value placeholder in [Proxy-]Authorizatio 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 reflect the stale value of uninitialized pool memory used by the prior

CVE-2018-1303 [HIGH] CWE-125 CVE-2018-1303: A specially crafted HTTP request header could have crashed the Apache HTTP Server prior to version 2 A specially crafted HTTP request header could have crashed the Apache HTTP Server prior to version 2.4.30 due to an out of bound read while preparing data to be cached in shared memory. It could be used as a Denial of Service attack against users of mod_cache_socache. The vulnerability is considered as low risk since mod_cache_socache is not widely used

CVE-2019-0190 [HIGH] CVE-2019-0190: A bug exists in the way mod_ssl handled client renegotiations. A remote attacker could send a carefu A bug exists in the way mod_ssl handled client renegotiations. A remote attacker could send a carefully crafted request that would cause mod_ssl to enter a loop leading to a denial of service. This bug can be only triggered with Apache HTTP Server version 2.4.37 when using OpenSSL version 1.1.1 or later, due to an interaction in changes to handling of renegotia

CVE-2017-7659 [HIGH] CWE-476 CVE-2017-7659: A maliciously constructed HTTP/2 request could cause mod_http2 in Apache HTTP Server 2.4.24, 2.4.25 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.

CVE-2017-7668 [HIGH] CWE-126 CVE-2017-7668: The HTTP strict parsing changes added in Apache httpd 2.2.32 and 2.4.24 introduced a bug in token li 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.

CVE-2018-11763 [MEDIUM] CVE-2018-11763: In Apache HTTP Server 2.4.17 to 2.4.34, by sending continuous, large SETTINGS frames a client can oc In Apache HTTP Server 2.4.17 to 2.4.34, by sending continuous, large SETTINGS frames a client can occupy a connection, server thread and CPU time without any connection timeout coming to effect. This affects only HTTP/2 connections. A possible mitigation is to not enable the h2 protocol.

CVE-2021-44790 [CRITICAL] CWE-787 CVE-2021-44790: A carefully crafted request body can cause a buffer overflow in the mod_lua multipart parser (r:pars A carefully crafted request body can cause a buffer overflow in the mod_lua multipart parser (r:parsebody() called from Lua scripts). The Apache httpd team is not aware of an exploit for the vulnerabilty though it might be possible to craft one. This issue affects Apache HTTP Server 2.4.51 and earlier.

CVE-2026-23918 [HIGH] CWE-415 CVE-2026-23918: Double Free and possible RCE vulnerability in Apache HTTP Server with the HTTP/2 protocol. This iss Double Free and possible RCE vulnerability in Apache HTTP Server with the HTTP/2 protocol. This issue affects Apache HTTP Server: 2.4.66. Users are recommended to upgrade to version 2.4.67, which fixes the issue.

CVE-2024-38472 [HIGH] CWE-918 CVE-2024-38472: SSRF in Apache HTTP Server on Windows allows to potentially leak NTLM hashes to a malicious server v SSRF in Apache HTTP Server on Windows allows to potentially leak NTLM hashes to a malicious server via SSRF and malicious requests or content Users are recommended to upgrade to version 2.4.60 which fixes this issue. Note: Existing configurations that access UNC paths will have to configure new directive "UNCList" to allow access during request proces

CVE-2016-8740 [HIGH] CWE-20 CVE-2016-8740: The mod_http2 module in the Apache HTTP Server 2.4.17 through 2.4.23, when the Protocols configurati 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 an HTTP/2 request.

CVE-2024-38473 [HIGH] CWE-116 CVE-2024-38473: Encoding problem in mod_proxy in Apache HTTP Server 2.4.59 and earlier allows request URLs with inco 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.

CVE-2021-26691 [CRITICAL] CWE-122 CVE-2021-26691: In Apache HTTP Server versions 2.4.0 to 2.4.46 a specially crafted SessionHeader sent by an origin s In Apache HTTP Server versions 2.4.0 to 2.4.46 a specially crafted SessionHeader sent by an origin server could cause a heap overflow