Apache Software Foundation Apache Http Server vulnerabilities

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-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-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.

CVE-2022-31813 [CRITICAL] CWE-348 CVE-2022-31813: Apache HTTP Server 2.4.53 and earlier may not send the X-Forwarded-* headers to the origin server ba Apache HTTP Server 2.4.53 and earlier may not send the X-Forwarded-* headers to the origin server based on client side Connection header hop-by-hop mechanism. This may be used to bypass IP based authentication on the origin server/application.

CVE-2024-38474 [CRITICAL] CWE-116 CVE-2024-38474: Substitution encoding issue in mod_rewrite in Apache HTTP Server 2.4.59 and earlier allows attacker Substitution encoding issue in mod_rewrite in Apache HTTP Server 2.4.59 and earlier allows attacker to execute scripts in directories permitted by the configuration but not directly reachable by any URL or source disclosure of scripts meant to only to be executed as CGI. Users are recommended to upgrade to version 2.4.60, which fixes this issue.

CVE-2017-3169 [CRITICAL] CWE-476 CVE-2017-3169: 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 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.

CVE-2019-17567 [MEDIUM] CWE-444 CVE-2019-17567: Apache HTTP Server versions 2.4.6 to 2.4.46 mod_proxy_wstunnel configured on an URL that is not nece 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.

CVE-2026-29167 [CRITICAL] CWE-416 CVE-2026-29167: Use After Free vulnerability in Apache HTTP Server with mod_ldap in per-directory configuration Thi Use After Free vulnerability in Apache HTTP Server with mod_ldap in per-directory configuration This issue affects Apache HTTP Server: from 2.4.0 through 2.4.67. Users are recommended to upgrade to version 2.4.68, which fixes the issue.

CVE-2026-44631 [CRITICAL] CWE-124 CVE-2026-44631: Buffer Underwrite vulnerability in Apache HTTP Server on crafted regular expressions in the configur Buffer Underwrite vulnerability in Apache HTTP Server on crafted regular expressions in the configuration. This issue affects Apache HTTP Server: from 2.4.0 through 2.4.67. Users are recommended to upgrade to version 2.4.68, which fixes the issue.

CVE-2021-41524 [HIGH] CWE-476 CVE-2021-41524: While fuzzing the 2.4.49 httpd, a new null pointer dereference was detected during HTTP/2 request pr While fuzzing the 2.4.49 httpd, a new null pointer dereference was detected during HTTP/2 request processing, allowing an external source to DoS the server. This requires a specially crafted request. The vulnerability was recently introduced in version 2.4.49. No exploit is known to the project.

CVE-2022-26377 [HIGH] CWE-444 CVE-2022-26377: Inconsistent Interpretation of HTTP Requests ('HTTP Request Smuggling') vulnerability in mod_proxy_a 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.

CVE-2026-24072 [HIGH] CWE-269 CVE-2026-24072: An escalation of privilege bug in various modules in Apache HTTP 2.4.66 and earlier allows local .ht An escalation of privilege bug in various modules in Apache HTTP 2.4.66 and earlier allows local .htaccess authors to read files with the privileges of the httpd user. Users are recommended to upgrade to version 2.4.67, which fixes this issue.

CVE-2025-23048 [CRITICAL] CWE-284 CVE-2025-23048: In some mod_ssl configurations on Apache HTTP Server 2.4.35 through to 2.4.63, an access control byp In some mod_ssl configurations on Apache HTTP Server 2.4.35 through to 2.4.63, an access control bypass by trusted clients is possible using TLS 1.3 session resumption. Configurations are affected when mod_ssl is configured for multiple virtual hosts, with each restricted to a different set of trusted client certificates (for example with a diffe

CVE-2022-36760 [CRITICAL] CWE-444 CVE-2022-36760: Inconsistent Interpretation of HTTP Requests ('HTTP Request Smuggling') vulnerability in mod_proxy_a 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 2.4.54 and prior versions.

CVE-2025-58098 [HIGH] CWE-201 CVE-2025-58098: Apache HTTP Server 2.4.65 and earlier with Server Side Includes (SSI) enabled and mod_cgid (but not Apache HTTP Server 2.4.65 and earlier with Server Side Includes (SSI) enabled and mod_cgid (but not mod_cgi) passes the shell-escaped query string to #exec cmd="..." directives. This issue affects Apache HTTP Server before 2.4.66. Users are recommended to upgrade to version 2.4.66, which fixes the issue.

CVE-2022-28615 [CRITICAL] CWE-190 CVE-2022-28615: Apache HTTP Server 2.4.53 and earlier may crash or disclose information due to a read beyond bounds Apache HTTP Server 2.4.53 and earlier may crash or disclose information due to a read beyond bounds in ap_strcmp_match() when provided with an extremely large input buffer. While no code distributed with the server can be coerced into such a call, third-party modules or lua scripts that use ap_strcmp_match() may hypothetically be affected.

CVE-2018-17199 [HIGH] CWE-384 CVE-2018-17199: In Apache HTTP Server 2.4 release 2.4.37 and prior, mod_session checks the session expiry time befor 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.

CVE-2026-42535 [CRITICAL] CWE-668 CVE-2026-42535: A path handling issue in mod_dav_fs in Apache 2.4.67 and earlier allows a WebDAV content author to d A path handling issue in mod_dav_fs in Apache 2.4.67 and earlier allows a WebDAV content author to directly manipulate trusted DAV property databases, potentially causing child process crashes. Users are recommended to upgrade to version 2.4.68, which fixes this issue.

CVE-2022-37436 [MEDIUM] CWE-113 CVE-2022-37436: Prior to Apache HTTP Server 2.4.55, a malicious backend can cause the response headers to be truncat 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.