HAProxy Vulnerabilities and Affected Products

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Explore source-attributed vulnerabilities associated with HAProxy products.

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Showing 9 vulnerabilities on this page

Signals CISA KEV Ransomware Nuclei
VulnerabilityTitle and contextCVSSEPSSPoCsSignals

HAProxy Missing Length Check in NEW_TOKEN Format

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.

CWE-130Jul 20, 2026
CVSS4.8v3.1EPSS0.363%PoCs0SignalsSTIX

HAProxy varint Mishandling Loop or Crash

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.

CWE-252Jul 20, 2026
CVSS3.7v3.1EPSS0.416%PoCs0SignalsSTIX

HAProxy - NULL Pointer Dereference in hpack_dht_insert Function

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.

CWE-476Jun 18, 2026
CVSS8.7v4.0EPSS0.484%PoCs0SignalsSTIX

HAProxy - Integer Overflow in FCGI Demux Record Length Field

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.

CWE-190Jun 18, 2026
CVSS9.0v4.0EPSS0.347%PoCs0SignalsSTIX

HAProxy HTTP/3 Request Smuggling via Standalone FIN Body Validation Bypass

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.

CWE-130Apr 13, 2026
CVSS4.0v3.1EPSS0.297%PoCs1SignalsSTIX

HAProxy Kubernetes Ingress Controller before 3.1.13, when the config-snippets feature flag is used, accepts config snippets from users with create/update permissions. This can result in obtaining an ingress token secret as a response. The fixed versions of HAProxy Enterprise Kubernetes Ingress Controller are 3.0.16-ee1, 1.11.13-ee1, and 1.9.15-ee1.

CWE-791Oct 8, 2025
CVSS6.4v3.1EPSS0.243%PoCs0SignalsSTIX

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.

CWE-1025Apr 9, 2025
CVSS6.8v3.1EPSS0.72%PoCs0SignalsSTIX

Inconsistent interpretation of HTTP requests ('HTTP Request/Response Smuggling') issue exists in HAProxy. If this vulnerability is exploited, a remote attacker may access a path that is restricted by ACL (Access Control List) set on the product. As a result, the attacker may obtain sensitive information.

CWE-444Nov 28, 2024
CVSS5.3v3.0EPSS1.04%PoCs0SignalsSTIX

HAProxy Endless Loop HTTP/2 Vulnerability

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.

CWE-835Sep 4, 2024
CVSS7.5v3.1EPSS1.2%PoCs0SignalsSTIX