Vulnerability Database

309,961

Total vulnerabilities in the database

CVE-2021-40346

An integer overflow exists in HAProxy 2.0 through 2.5 in htx_add_header that can be exploited to perform an HTTP request smuggling attack, allowing an attacker to bypass all configured http-request HAProxy ACLs and possibly other ACLs.

  • Published: Sep 8, 2021
  • Updated: Nov 16, 2025
  • CVE: CVE-2021-40346
  • Severity: High
  • Exploit:

CVSS v3:

  • Severity: High
  • Score: 7.5
  • AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

CVSS v2:

  • Severity: Medium
  • Score: 5
  • AV:N/AC:L/Au:N/C:N/I:P/A:N

CWEs:

Software From Fixed in
haproxy / haproxy 2.4.0 2.4.4
haproxy / haproxy 2.3.0 2.3.14
haproxy / haproxy 2.2.0 2.2.17
haproxy / haproxy 2.0.0 2.0.25
haproxy / haproxy 2.5-dev1 2.5-dev1.x
haproxy / haproxy 2.5-dev2 2.5-dev2.x
haproxy / haproxy 2.5-dev3 2.5-dev3.x
haproxy / haproxy 2.5-dev4 2.5-dev4.x
haproxy / haproxy 2.5-dev5 2.5-dev5.x
haproxy / haproxy 2.5-dev6 2.5-dev6.x
haproxy / haproxy 2.5-dev0 2.5-dev0.x
debian / debian_linux 11.0 11.0.x
fedoraproject / fedora 33 33.x
fedoraproject / fedora 34 34.x