Apache Http Server vulnerabilities

CVE-2021-34798 [HIGH] CWE-476 CVE-2021-34798: Malformed requests may cause the server to dereference a NULL pointer. This issue affects Apache HTT Malformed requests may cause the server to dereference a NULL pointer. This issue affects Apache HTTP Server 2.4.48 and earlier.

CVE-2018-1312 [CRITICAL] CWE-287 CVE-2018-1312: In Apache httpd 2.2.0 to 2.4.29, when generating an HTTP Digest authentication challenge, the nonce In Apache httpd 2.2.0 to 2.4.29, when generating an HTTP Digest authentication challenge, the nonce sent to prevent reply attacks was not correctly generated using a pseudo-random seed. In a cluster of servers using a common Digest authentication configuration, HTTP requests could be replayed across servers by an attacker without detection.

CVE-2017-7679 [CRITICAL] CWE-126 CVE-2017-7679: 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 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.

CVE-2021-26690 [HIGH] CWE-476 CVE-2021-26690: Apache HTTP Server versions 2.4.0 to 2.4.46 A specially crafted Cookie header handled by mod_session Apache HTTP Server versions 2.4.0 to 2.4.46 A specially crafted Cookie header handled by mod_session can cause a NULL pointer dereference and crash, leading to a possible Denial Of Service

CVE-2020-11993 [HIGH] CWE-444 CVE-2020-11993: Apache HTTP Server versions 2.4.20 to 2.4.43 When trace/debug was enabled for the HTTP/2 module and Apache HTTP Server versions 2.4.20 to 2.4.43 When trace/debug was enabled for the HTTP/2 module and on certain traffic edge patterns, logging statements were made on the wrong connection, causing concurrent use of memory pools. Configuring the LogLevel of mod_http2 above "info" will mitigate this vulnerability for unpatched servers.

CVE-2021-33193 [HIGH] CVE-2021-33193: A crafted method sent through HTTP/2 will bypass validation and be forwarded by mod_proxy, which can 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.

CVE-2003-0245 [MEDIUM] CVE-2003-0245: Vulnerability in the apr_psprintf function in the Apache Portable Runtime (APR) library for Apache 2 Vulnerability in the apr_psprintf function in the Apache Portable Runtime (APR) library for Apache 2.0.37 through 2.0.45 allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via long strings, as demonstrated using XML objects to mod_dav, and possibly other vectors.

CVE-2024-39573 [HIGH] CWE-20 CVE-2024-39573: Potential SSRF in mod_rewrite in Apache HTTP Server 2.4.59 and earlier allows an attacker to cause u Potential SSRF in mod_rewrite in Apache HTTP Server 2.4.59 and earlier allows an attacker to cause unsafe RewriteRules to unexpectedly setup URL's to be handled by mod_proxy. Users are recommended to upgrade to version 2.4.60, which fixes this issue.

CVE-2002-2029 [HIGH] CVE-2002-2029: PHP, when installed on Windows with Apache and ScriptAlias for /php/ set to c:/php/, allows remote a PHP, when installed on Windows with Apache and ScriptAlias for /php/ set to c:/php/, allows remote attackers to read arbitrary files and possibly execute arbitrary programs via an HTTP request for php.exe with a filename in the query string.

CVE-2021-31618 [HIGH] CWE-476 CVE-2021-31618: Apache HTTP Server protocol handler for the HTTP/2 protocol checks received request headers against Apache HTTP Server protocol handler for the HTTP/2 protocol checks received request headers against the size limitations as configured for the server and used for the HTTP/1 protocol as well. On violation of these restrictions and HTTP response is sent to the client with a status code indicating why the request was rejected. This rejection response was

CVE-2006-3918 [MEDIUM] CWE-79 CVE-2006-3918: http_protocol.c in (1) IBM HTTP Server 6.0 before 6.0.2.13 and 6.1 before 6.1.0.1, and (2) Apache HT http_protocol.c in (1) IBM HTTP Server 6.0 before 6.0.2.13 and 6.1 before 6.1.0.1, and (2) Apache HTTP Server 1.3 before 1.3.35, 2.0 before 2.0.58, and 2.2 before 2.2.2, does not sanitize the Expect header from an HTTP request when it is reflected back in an error message, which might allow cross-site scripting (XSS) style attacks using web client comp

CVE-2008-0455 [MEDIUM] CWE-79 CVE-2008-0455: Cross-site scripting (XSS) vulnerability in the mod_negotiation module in the Apache HTTP Server 2.2 Cross-site scripting (XSS) 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 web script or HTML by uploading a file with a name containing XSS sequences and a

CVE-2003-0132 [MEDIUM] CWE-772 CVE-2003-0132: A memory leak in Apache 2.0 through 2.0.44 allows remote attackers to cause a denial of service (mem A memory leak in Apache 2.0 through 2.0.44 allows remote attackers to cause a denial of service (memory consumption) via large chunks of linefeed characters, which causes Apache to allocate 80 bytes for each linefeed.

CVE-2007-6203 [MEDIUM] CVE-2007-6203: Apache HTTP Server 2.0.x and 2.2.x does not sanitize the HTTP Method specifier header from an HTTP r Apache HTTP Server 2.0.x and 2.2.x does not sanitize the HTTP Method specifier header from an HTTP request when it is reflected back in a "413 Request Entity Too Large" error message, which might allow cross-site scripting (XSS) style attacks using web client components that can send arbitrary headers in requests, as demonstrated via an HTTP request containin

CVE-1999-0067 [CRITICAL] CWE-78 CVE-1999-0067: phf CGI program allows remote command execution through shell metacharacters. phf CGI program allows remote command execution through shell metacharacters.

CVE-2001-0731 [MEDIUM] CVE-2001-0731: Apache 1.3.20 with Multiviews enabled allows remote attackers to view directory contents and bypass Apache 1.3.20 with Multiviews enabled allows remote attackers to view directory contents and bypass the index page via a URL containing the "M=D" query string.

CVE-2026-28780 [CRITICAL] CWE-122 CVE-2026-28780: Heap-based Buffer Overflow vulnerability in mod_proxy_ajp of Apache HTTP Server. If mod_proxy_ajp co Heap-based Buffer Overflow vulnerability in mod_proxy_ajp of Apache HTTP Server. If mod_proxy_ajp connects to a malicious AJP server this AJP server can send a malicious AJP message back to mod_proxy_ajp and cause it to write 4 attacker controlled bytes after the end of a heap based buffer. This issue affects Apache HTTP Server: through 2.4.66.

CVE-2020-13950 [HIGH] CWE-476 CVE-2020-13950: Apache HTTP Server versions 2.4.41 to 2.4.46 mod_proxy_http can be made to crash (NULL pointer deref Apache HTTP Server versions 2.4.41 to 2.4.46 mod_proxy_http can be made to crash (NULL pointer dereference) with specially crafted requests using both Content-Length and Transfer-Encoding headers, leading to a Denial of Service

CVE-2016-4979 [HIGH] CWE-284 CVE-2016-4979: The Apache HTTP Server 2.4.18 through 2.4.20, when mod_http2 and mod_ssl are enabled, does not prope 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 ability to send multiple requests over a single connection and aborting a renego

CVE-2026-49975 [HIGH] CWE-789 CVE-2026-49975: Memory Allocation with Excessive Size Value vulnerability in Apache HTTP Server's mod_http leads to Memory Allocation with Excessive Size Value vulnerability in Apache HTTP Server's mod_http leads to denial of service via malicious HTTP requests. This issue affects Apache HTTP Server: from 2.4.17 through 2.4.67.