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.

CVSS v3.1 NVD

7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

CVSS v2.0 NVD

5.0 MEDIUMAV:N/AC:L/Au:N/C:N/I:P/A:N

EPSS

58.83% chance of exploitation in the next 30 days, 99th percentile

Published

2021-09-08

Updated

2024-08-04

Proof-of-concept exploits (7)

• Vulnmachines/HAProxy_CVE-2021-403465★ · 2022-09-20
• alexOarga/CVE-2021-403460★ · 2022-01-24
• alikarimi999/CVE-2021-403465★ · 2021-09-13
• donky16/CVE-2021-40346-POC32★ · 2021-09-28
• knqyf263/CVE-2021-4034641★ · 2021-09-08
• rizemon/CS53312★ · 2023-04-25
• jmg0929/CVE-2021-403460★ · 2026-07-09

Security advisories

• https://git.haproxy.org/?p=haproxy.git
• haproxy/haproxy/commit/3b69886f7dcc3cfb3d166309018e6cfec9ce2c95
• https://jfrog.com/blog/critical-vulnerability-in-haproxy-cve-2021-40346-integer-overflow-…
• https://www.debian.org/security/2021/dsa-4968

References

• CVE Record
• NVD entry

Related

• CVE-2019-19781
• CVE-2019-6339
• CVE-2020-8417
• CVE-2020-9496
• CVE-2021-2109
• CVE-2021-21972