144 results · Feed
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Medium 5.3
Apache HTTP Server: mod_proxy_ajp: Heap Buffer Over-Read Due to Missing Null-Termination Check (ajp_msg_get_string)
Improper Null Termination, Out-of-bounds Read vulnerability in Apache HTTP Server. This issue affects Apache HTTP Server: through 2.4.66. Users are recommended to upgrade to version 2.4.67, which fixes the issue.
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High 7.5
Apache HTTP Server: mod_proxy_ajp: Heap Over-Read and memory disclosure in ajp_parse_data()
Buffer Over-read vulnerability in Apache HTTP Server. This issue affects Apache HTTP Server: through 2.4.66. Users are recommended to upgrade to version 2.4.67, which fixes the issue.
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High 8.8CVE-2026-24072 Public exploit
Apache HTTP Server: mod_rewrite elevation of privileges via ap_expr
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.
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High 8.3CVE-2025-58098 Public exploit
Apache HTTP Server: Server Side Includes adds query string to #exec cmd=...
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 upg…
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Medium 5.4
Apache HTTP Server: mod_userdir+suexec bypass via AllowOverride FileInfo
mod_userdir+suexec bypass via AllowOverride FileInfo vulnerability in Apache HTTP Server. Users with access to use the RequestHeader directive in htaccess can cause some CGI scripts to run under an unexpected userid. This issue affects Apache HTTP Server: fro…
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Medium 6.5
Apache HTTP Server: CGI environment variable override
Improper Neutralization of Escape, Meta, or Control Sequences vulnerability in Apache HTTP Server through environment variables set via the Apache configuration unexpectedly superseding variables calculated by the server for CGI programs. This issue affects A…
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High 7.5
Apache HTTP Server: mod_md (ACME), unintended retry intervals
An integer overflow in the case of failed ACME certificate renewal leads, after a number of failures (~30 days in default configurations), to the backoff timer becoming 0. Attempts to renew the certificate then are repeated without delays until it succeeds. T…
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High 7.5CVE-2025-53020 Public exploit
Apache HTTP Server: HTTP/2 DoS by Memory Increase
Late Release of Memory after Effective Lifetime vulnerability in Apache HTTP Server. This issue affects Apache HTTP Server: from 2.4.17 up to 2.4.63. Users are recommended to upgrade to version 2.4.64, which fixes the issue.
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High 7.4CVE-2025-49812 Public exploit
Apache HTTP Server: mod_ssl TLS upgrade attack
In some mod_ssl configurations on Apache HTTP Server versions through to 2.4.63, an HTTP desynchronisation attack allows a man-in-the-middle attacker to hijack an HTTP session via a TLS upgrade. Only configurations using "SSLEngine optional" to enable TLS upg…
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High 7.5
Apache HTTP Server: mod_proxy_http2 denial of service
In certain proxy configurations, a denial of service attack against Apache HTTP Server versions 2.4.26 through to 2.4.63 can be triggered by untrusted clients causing an assertion in mod_proxy_http2. Configurations affected are a reverse proxy is configured f…
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Critical 9.1CVE-2025-23048 Public exploit
Apache HTTP Server: mod_ssl access control bypass with session resumption
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 ea…
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High 7.5
Apache HTTP Server: mod_ssl error log variable escaping
Insufficient escaping of user-supplied data in mod_ssl in Apache HTTP Server 2.4.63 and earlier allows an untrusted SSL/TLS client to insert escape characters into log files in some configurations. In a logging configuration where CustomLog is used with "%{va…
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High 7.5
Apache HTTP Server: SSRF with mod_headers setting Content-Type header
SSRF in Apache HTTP Server with mod_proxy loaded allows an attacker to send outbound proxy requests to a URL controlled by the attacker. Requires an unlikely configuration where mod_headers is configured to modify the Content-Type request or response header …
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High 7.5
Apache HTTP Server: HTTP response splitting
HTTP response splitting in the core of Apache HTTP Server allows an attacker who can manipulate the Content-Type response headers of applications hosted or proxied by the server can split the HTTP response. This vulnerability was described as CVE-2023-38709 b…
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Medium 5.3CVE-2024-40725 Public exploit
Apache HTTP Server: source code disclosure with handlers configured via AddType
A partial fix for CVE-2024-39884 in the core of Apache HTTP Server 2.4.61 ignores some use of the legacy content-type based configuration of handlers. "AddType" and similar configuration, under some circumstances where files are requested indirectly, result …
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Medium 6.2
Apache HTTP Server: source code disclosure with handlers configured via AddType
A regression in the core of Apache HTTP Server 2.4.60 ignores some use of the legacy content-type based configuration of handlers. "AddType" and similar configuration, under some circumstances where files are requested indirectly, result in source code disc…
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High 7.5CVE-2024-39573 EPSS 35%
Apache HTTP Server: mod_rewrite proxy handler substitution
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.
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High 7.5
Apache HTTP Server: Crash resulting in Denial of Service in mod_proxy via a malicious request
null pointer dereference in mod_proxy in Apache HTTP Server 2.4.59 and earlier allows an attacker to crash the server via a malicious request. Users are recommended to upgrade to version 2.4.60, which fixes this issue.
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Critical 9.8
Apache HTTP Server may use exploitable/malicious backend application output to run local handlers via internal redirect
Vulnerability in core of Apache HTTP Server 2.4.59 and earlier are vulnerably to information disclosure, SSRF or local script execution via backend applications whose response headers are malicious or exploitable. Users are recommended to upgrade to version 2…
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Critical 9.1
Apache HTTP Server weakness in mod_rewrite when first segment of substitution matches filesystem path.
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…
KEV May 1, 2025 -
High 8.1
Apache HTTP Server weakness with encoded question marks in backreferences
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 exec…
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High 8.1
Apache HTTP Server proxy encoding problem
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, w…
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Medium 5.4
Apache HTTP Server: DoS by Null pointer in websocket over HTTP/2
Serving WebSocket protocol upgrades over a HTTP/2 connection could result in a Null Pointer dereference, leading to a crash of the server process, degrading performance.
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High 7.5
Apache HTTP Server: HTTP/2 DoS by memory exhaustion on endless continuation frames
HTTP/2 incoming headers exceeding the limit are temporarily buffered in nghttp2 in order to generate an informative HTTP 413 response. If a client does not stop sending headers, this leads to memory exhaustion.
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Medium 6.3
Apache HTTP Server: HTTP Response Splitting in multiple modules
HTTP Response splitting in multiple modules in Apache HTTP Server allows an attacker that can inject malicious response headers into backend applications to cause an HTTP desynchronization attack. Users are recommended to upgrade to version 2.4.59, which fixe…
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High 7.3CVE-2023-38709 Public exploit
Apache HTTP Server: HTTP response splitting
Faulty input validation in the core of Apache allows malicious or exploitable backend/content generators to split HTTP responses. This issue affects Apache HTTP Server: through 2.4.58.
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Unscored —
Apache HTTP Server: mod_macro buffer over-read
Out-of-bounds Read vulnerability in mod_macro of Apache HTTP Server.This issue affects Apache HTTP Server: through 2.4.57.
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Unscored —CVE-2023-45802 Public exploit
Apache HTTP Server: HTTP/2 stream memory not reclaimed right away on RST
When a HTTP/2 stream was reset (RST frame) by a client, there was a time window were the request's memory resources were not reclaimed immediately. Instead, de-allocation was deferred to connection close. A client could send new requests and resets, keeping t…
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High 7.5
Apache HTTP Server: mod_proxy_uwsgi HTTP response splitting
HTTP Response Smuggling vulnerability in Apache HTTP Server via mod_proxy_uwsgi. This issue affects Apache HTTP Server: from 2.4.30 through 2.4.55. Special characters in the origin response header can truncate/split the response forwarded to the client.
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Critical 9.8
Apache HTTP Server: HTTP request splitting with mod_rewrite and mod_proxy
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 patter…
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Medium 5.3CVE-2022-37436 EPSS 53%
Apache HTTP Server: mod_proxy prior to 2.4.55 allows a backend to trigger HTTP response splitting
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 …
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Critical 9.0
Apache HTTP Server: mod_proxy_ajp Possible request smuggling
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 Se…
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Unscored —CVE-2006-20001 Public exploit
Apache HTTP Server: mod_dav out of bounds read, or write of zero byte
A carefully crafted If: request header can cause a memory read, or write of a single zero byte, in a pool (heap) memory location beyond the header value sent. This could cause the process to crash. This issue affects Apache HTTP Server 2.4.54 and earlier.
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Unscored —CVE-2022-31813 Public exploit
mod_proxy X-Forwarded-For dropped by hop-by-hop mechanism
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.
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Unscored —
Information Disclosure in mod_lua with websockets
Apache HTTP Server 2.4.53 and earlier may return lengths to applications calling r:wsread() that point past the end of the storage allocated for the buffer.
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Unscored —CVE-2022-30522 EPSS 90%
mod_sed denial of service
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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Unscored —
Denial of service in mod_lua r:parsebody
In Apache HTTP Server 2.4.53 and earlier, a malicious request to a lua script that calls r:parsebody(0) may cause a denial of service due to no default limit on possible input size.
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Critical 9.1
Read beyond bounds in ap_strcmp_match()
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…
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Unscored —
read beyond bounds via ap_rwrite()
The ap_rwrite() function in Apache HTTP Server 2.4.53 and earlier may read unintended memory if an attacker can cause the server to reflect very large input using ap_rwrite() or ap_rputs(), such as with mod_luas r:puts() function. Modules compiled and distrib…
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Unscored —
mod_proxy_ajp: Possible request smuggling
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 Se…