Haproxy vulnerabilities, page 2
41 vulnerabilities
Known vulnerabilities in Haproxy products, newest first, with CVSS severity, EPSS, KEV listings and ransomware use, across 11 products.
CVE-2025-32464chainguardhaproxy-2.4+16
EPSS score0.76%
HAProxy 2.2 through 3.1.6, in certain uncommon configurations, has a sample_conv_regsub heap-based buffer overflow because of mishandling of the replacement of multiple short patterns with a longer one.CVE-2020-11100alpinehaproxy+17EPSS score61.59%
In hpack_dht_insert in hpack-tbl.c in the HPACK decoder in HAProxy 1.8 through 2.x before 2.1.4, a remote attacker can write arbitrary bytes around a certain location on the heap via a crafted HTTP/2 request, possibly causing remote code execution.CVE-2014-6269debianhaproxy+4EPSS score3.81%
Multiple integer overflows in the http_request_forward_body function in proto_http.c in HAProxy 1.5-dev23 before 1.5.4 allow remote attackers to cause a denial of service (crash) via a large stream of data, which triggers a buffer overflow and an out-of-bounds read.CVE-2022-0711alpinehaproxy+17EPSS score16.56%
A flaw was found in the way HAProxy processed HTTP responses containing the "Set-Cookie2" header. This flaw could allow an attacker to send crafted HTTP response packets which lead to an infinite loop, eventually resulting in a denial of service condition. The highest threat from this vulnerability is availability.CVE-2012-2942debianhaproxy+1EPSS score5.35%
Buffer overflow in the trash buffer in the header capture functionality in HAProxy before 1.4.21, when global.tune.bufsize is set to a value greater than the default and header rewriting is enabled, allows remote attackers to cause a denial of service and possibly execute arbitrary code via unspecified vectors.CVE-2024-45506chainguardhaproxy-3.0+4EPSS score1.20%
HAProxy 2.9.x before 2.9.10, 3.0.x before 3.0.4, and 3.1.x through 3.1-dev6 allows a remote denial of service for HTTP/2 zero-copy forwarding (h2_send loop) under a certain set of conditions, as exploited in the wild in 2024.CVE-2019-19330alpinehaproxy+5EPSS score4.03%
The HTTP/2 implementation in HAProxy before 2.0.10 mishandles headers, as demonstrated by carriage return (CR, ASCII 0xd), line feed (LF, ASCII 0xa), and the zero character (NUL, ASCII 0x0), aka Intermediary Encapsulation Attacks.CVE-2019-11323haproxyhaproxyEPSS score1.25%
HAProxy before 1.9.7 mishandles a reload with rotated keys, which triggers use of uninitialized, and very predictable, HMAC keys. This is related to an include/types/ssl_sock.h error.CVE-2019-14241haproxyhaproxy+4EPSS score70.24%
HAProxy through 2.0.2 allows attackers to cause a denial of service (ha_panic) via vectors related to htx_manage_client_side_cookies in proto_htx.c.CVE-2019-14243github.com/mastercactapusproxyprotocol+1EPSS score4.29%
headerv2.go in mastercactapus proxyprotocol before 0.0.2, as used in the mastercactapus caddy-proxyprotocol plugin through 0.0.2 for Caddy, allows remote attackers to cause a denial of service (webserver panic and daemon crash) via a crafted HAProxy PROXY v2 request with truncated source/destination address data.CVE-2019-18277debianhaproxy+15EPSS score10.07%
A flaw was found in HAProxy before 2.0.6. In legacy mode, messages featuring a transfer-encoding header missing the "chunked" value were not being correctly rejected. The impact was limited but if combined with the "http-reuse always" setting, it could be used to help construct an HTTP request smuggling attack against a vulnerable component employing a lenient parser that would ignore the content-length header as soon as it saw a transfer-encoding one (even if not entirely valid according to the specification).CVE-2026-55204chainguardhaproxy-2.4+14EPSS score0.48%
HAProxy through 3.4.0, fixed in commit 9a6d1fe, contains a null pointer dereference vulnerability in hpack_dht_insert() within src/hpack-tbl.c that fails to validate the return value of hpack_dht_defrag() when the memory pool is exhausted. An attacker can trigger HPACK dynamic table insertions under memory pressure to dereference a NULL pointer and crash HAProxy worker processes, causing denial of service.CVE-2026-55203chainguardhaproxy-2.4+11EPSS score0.33%
HAProxy through 3.4.0, fixed in commit 5985276, contains an integer overflow vulnerability in the fcgi_conn structure's drl field that allows buffer misparse as new FCGI record headers. When contentLength is 65535 and paddingLength is 1 or more, the drl field wraps to 0, causing incorrect record consumption and allowing malicious FastCGI backends to desynchronize the FCGI framing parser, potentially causing request routing errors, response smuggling, or memory safety issues.CVE-2026-26080debianhaproxy+3EPSS score0.55%
HAProxy Community Edition 3.2.x through 3.3.x before 3.3.3 can enter a loop or crash because varint is mishandled. HAProxy Enterprise and ALOHA are also affected.CVE-2026-26081debianhaproxy+5EPSS score0.48%
HAProxy Community Edition 3.0 through 3.3 before 3.3.3 lacks a length check for the NEW_TOKEN format. HAProxy Enterprise and ALOHA are also affected.CVE-2026-90678ubuntuhaproxy+2EPSS score0.77%
An issue was discovered in HAProxy 3.3.0 through 3.4.4 and in 3.5-dev1 through 3.5-dev5. Exploitation requires an HTTP/3 frontend: HAProxy must be built with QUIC support and configured with a QUIC bind listener, and the affected traffic must reach a backend over HTTP/1.1 using chunked transfer coding on a reused connection. Under those conditions, when an HTTP/3 request carries no Content-Length header, the HTTP/3 multiplexer credits the length declared in a DATA frame header to the stream endpoint's known-input-payload estimate at the moment the frame header is decoded, before the payload has been received, and that declared length is emitted verbatim as the HTTP/1.1 chunk size. A remote unauthenticated client that declares more payload than it delivers and then ends the stream causes HAProxy to announce a chunk larger than the bytes it writes and to return the connection to the idle pool in a desynchronized state. The result is potential HTTP request smuggling on reused backend connections: an attacker can place a request past a frontend rule such as a path-based http-request deny, so that the smuggled request is never seen by HAProxy's HTTP analysis, and can cause concurrent clients' requests, including their request lines and Authorization headers, to be consumed as the attacker's request body and lost. Exploitation is not deterministic; it depends on a race with backend connection pooling, succeeding in a majority of but not all trials during testing, and can be retried freely. The mechanism was introduced in 3.3-dev10; releases 3.2.x and earlier are unaffected.CVE-2026-33555chainguardhaproxy-2.6+15EPSS score0.60%
An issue was discovered in HAProxy before 3.3.6. The HTTP/3 parser does not check that the received body length matches a previously announced content-length when the stream is closed via a frame with an empty payload. This can cause desynchronization issues with the backend server and could be used for request smuggling. The earliest affected version is 2.6.CVE-2023-40225debianhaproxy+18EPSS score2.15%
HAProxy through 2.0.32, 2.1.x and 2.2.x through 2.2.30, 2.3.x and 2.4.x through 2.4.23, 2.5.x and 2.6.x before 2.6.15, 2.7.x before 2.7.10, and 2.8.x before 2.8.2 forwards empty Content-Length headers, violating RFC 9110 section 8.6. In uncommon cases, an HTTP/1 server behind HAProxy may interpret the payload as an extra request.CVE-2023-0836debianhaproxy+5EPSS score1.20%
An information leak vulnerability was discovered in HAProxy 2.1, 2.2 before 2.2.27, 2.3, 2.4 before 2.4.21, 2.5 before 2.5.11, 2.6 before 2.6.8, 2.7 before 2.7.1. There are 5 bytes left uninitialized in the connection buffer when encoding the FCGI_BEGIN_REQUEST record. Sensitive data may be disclosed to configured FastCGI backends in an unexpected way.CVE-2023-0056chainguardhaproxy-2.4+27EPSS score1.83%
An uncontrolled resource consumption vulnerability was discovered in HAProxy which could crash the service. This issue could allow an authenticated remote attacker to run a specially crafted malicious server in an OpenShift cluster. The biggest impact is to availability.