7.5
HIGH
CVE-2021-40346
HAProxy HTTP Request Smuggling Integer Overflow Vulnerability
Description

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.

INFO

Published Date :

Sept. 8, 2021, 5:15 p.m.

Last Modified :

Nov. 21, 2024, 6:23 a.m.

Source :

[email protected]

Remotely Exploitable :

Yes !

Impact Score :

3.6

Exploitability Score :

3.9
Public PoC/Exploit Available at Github

CVE-2021-40346 has a 17 public PoC/Exploit available at Github. Go to the Public Exploits tab to see the list.

Affected Products

The following products are affected by CVE-2021-40346 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Fedoraproject fedora
1 Debian debian_linux
1 Haproxy haproxy
: Total Affected Vendor : 3 | Products : 3
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2021-40346.

URL Resource
https://git.haproxy.org/?p=haproxy.git Patch Vendor Advisory
https://github.com/haproxy/haproxy/commit/3b69886f7dcc3cfb3d166309018e6cfec9ce2c95 Patch Third Party Advisory
https://jfrog.com/blog/critical-vulnerability-in-haproxy-cve-2021-40346-integer-overflow-enables-http-smuggling/ Exploit Mitigation Third Party Advisory
https://lists.apache.org/thread.html/r284567dd7523f5823e2ce995f787ccd37b1cc4108779c50a97c79120%40%3Cdev.cloudstack.apache.org%3E
https://lists.apache.org/thread.html/r8a58fd7a29808e5d27ee56877745e58dc4bb041b9af94601554e2a5a%40%3Cdev.cloudstack.apache.org%3E
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/A7V2IYO22LWVBGUNZWVKNTMDV4KINLFO/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MXTSBY2TEAXWZVFQM3CXHJFRONX7PEMN/
https://www.debian.org/security/2021/dsa-4968 Third Party Advisory
https://www.mail-archive.com/haproxy%40formilux.org
https://www.mail-archive.com/haproxy%40formilux.org/msg41114.html
https://git.haproxy.org/?p=haproxy.git Patch Vendor Advisory
https://github.com/haproxy/haproxy/commit/3b69886f7dcc3cfb3d166309018e6cfec9ce2c95 Patch Third Party Advisory
https://jfrog.com/blog/critical-vulnerability-in-haproxy-cve-2021-40346-integer-overflow-enables-http-smuggling/ Exploit Mitigation Third Party Advisory
https://lists.apache.org/thread.html/r284567dd7523f5823e2ce995f787ccd37b1cc4108779c50a97c79120%40%3Cdev.cloudstack.apache.org%3E
https://lists.apache.org/thread.html/r8a58fd7a29808e5d27ee56877745e58dc4bb041b9af94601554e2a5a%40%3Cdev.cloudstack.apache.org%3E
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/A7V2IYO22LWVBGUNZWVKNTMDV4KINLFO/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MXTSBY2TEAXWZVFQM3CXHJFRONX7PEMN/
https://www.debian.org/security/2021/dsa-4968 Third Party Advisory
https://www.mail-archive.com/haproxy%40formilux.org
https://www.mail-archive.com/haproxy%40formilux.org/msg41114.html

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Profile Photo
whoami13apt/files2

None

Updated: 3 weeks, 6 days ago
1 stars 0 fork 0 watcher
Born at : May 16, 2024, 2:53 p.m. This repo has been linked 48 different CVEs too.
Profile Photo
NaInSec/CVE-PoC-in-GitHub

All CVE - PoC in GitHub

poc proofofconcept tester allcve cvegithub cvenew cvepoc cveupdate

Updated: 1 month, 2 weeks ago
8 stars 3 fork 3 watcher
Born at : March 22, 2024, 3:58 p.m. This repo has been linked 928 different CVEs too.
Profile Photo
zecool/cve

None

Updated: 9 months, 1 week ago
1 stars 0 fork 0 watcher
Born at : March 11, 2024, 1:21 p.m. This repo has been linked 930 different CVEs too.
Profile Photo
rizemon/CS5331

Vulnerable environment and PoC scripts to demonstrate possible impacts of HTTP request smuggling

http requestsmuggling gunicorn haproxy cve-2021-40346

Dockerfile Python

Updated: 1 year, 2 months ago
0 stars 0 fork 0 watcher
Born at : March 24, 2023, 10:10 a.m. This repo has been linked 1 different CVEs too.
Profile Photo
WhooAmii/POC_to_review

None

Updated: 10 months ago
2 stars 2 fork 2 watcher
Born at : Nov. 25, 2022, 5:43 p.m. This repo has been linked 930 different CVEs too.
Profile Photo
soosmile/POC

None

Updated: 5 months, 3 weeks ago
8 stars 1 fork 1 watcher
Born at : June 21, 2022, 7:45 a.m. This repo has been linked 943 different CVEs too.
Profile Photo
PwnAwan/Awesome-HTTPRequestSmuggling

None

Updated: 2 years, 10 months ago
0 stars 0 fork 0 watcher
Born at : Feb. 16, 2022, 3:01 a.m. This repo has been linked 3 different CVEs too.
Profile Photo
alexOarga/CVE-2021-40346

CVE-2021-40346 - HaProxy HTTP request smuggling through integer overflow

Dockerfile Python Shell HTML

Updated: 2 years, 10 months ago
0 stars 0 fork 0 watcher
Born at : Jan. 24, 2022, 10:16 p.m. This repo has been linked 1 different CVEs too.
Profile Photo
D4rkP0w4r/INTENT-CTF-2021

None

Updated: 3 years ago
1 stars 0 fork 0 watcher
Born at : Nov. 20, 2021, 1:25 p.m. This repo has been linked 1 different CVEs too.
Profile Photo
Vulnmachines/HAProxy_CVE-2021-40346

HAProxy CVE-2021-40346

Updated: 2 years, 3 months ago
5 stars 0 fork 0 watcher
Born at : Nov. 8, 2021, 11:53 a.m. This repo has been linked 1 different CVEs too.
Profile Photo
alikarimi999/CVE-2021-40346

None

Dockerfile Makefile C Perl Lua Python Vim Script Shell Roff C++

Updated: 4 months, 1 week ago
5 stars 0 fork 0 watcher
Born at : Sept. 10, 2021, 11:02 p.m. This repo has been linked 1 different CVEs too.
Profile Photo
donky16/CVE-2021-40346-POC

CVE-2021-40346 integer overflow enables http smuggling

Dockerfile Python

Updated: 2 weeks, 3 days ago
33 stars 6 fork 6 watcher
Born at : Sept. 10, 2021, 8:18 a.m. This repo has been linked 1 different CVEs too.
Profile Photo
knqyf263/CVE-2021-40346

CVE-2021-40346 PoC (HAProxy HTTP Smuggling)

Dockerfile JavaScript Shell

Updated: 2 weeks, 3 days ago
38 stars 13 fork 13 watcher
Born at : Sept. 8, 2021, 10:26 p.m. This repo has been linked 1 different CVEs too.
Profile Photo
CHYbeta/OddProxyDemo

None

Dockerfile Python Shell JavaScript HTML

Updated: 2 weeks, 5 days ago
185 stars 20 fork 20 watcher
Born at : Aug. 25, 2021, 5:08 a.m. This repo has been linked 3 different CVEs too.
Profile Photo
izj007/wechat

微信收藏的文章

Updated: 2 weeks, 3 days ago
660 stars 128 fork 128 watcher
Born at : Aug. 3, 2021, 2:07 a.m. This repo has been linked 48 different CVEs too.

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2021-40346 vulnerability anywhere in the article.

The following table lists the changes that have been made to the CVE-2021-40346 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • CVE Modified by af854a3a-2127-422b-91ae-364da2661108

    Nov. 21, 2024

    Action Type Old Value New Value
    Added Reference https://git.haproxy.org/?p=haproxy.git
    Added Reference https://github.com/haproxy/haproxy/commit/3b69886f7dcc3cfb3d166309018e6cfec9ce2c95
    Added Reference https://jfrog.com/blog/critical-vulnerability-in-haproxy-cve-2021-40346-integer-overflow-enables-http-smuggling/
    Added Reference https://lists.apache.org/thread.html/r284567dd7523f5823e2ce995f787ccd37b1cc4108779c50a97c79120%40%3Cdev.cloudstack.apache.org%3E
    Added Reference https://lists.apache.org/thread.html/r8a58fd7a29808e5d27ee56877745e58dc4bb041b9af94601554e2a5a%40%3Cdev.cloudstack.apache.org%3E
    Added Reference https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/A7V2IYO22LWVBGUNZWVKNTMDV4KINLFO/
    Added Reference https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MXTSBY2TEAXWZVFQM3CXHJFRONX7PEMN/
    Added Reference https://www.debian.org/security/2021/dsa-4968
    Added Reference https://www.mail-archive.com/haproxy%40formilux.org
    Added Reference https://www.mail-archive.com/haproxy%40formilux.org/msg41114.html
  • CVE Modified by [email protected]

    May. 14, 2024

    Action Type Old Value New Value
  • CVE Modified by [email protected]

    Nov. 07, 2023

    Action Type Old Value New Value
    Added Reference MITRE https://www.mail-archive.com/haproxy%40formilux.org [No types assigned]
    Added Reference MITRE https://www.mail-archive.com/haproxy%40formilux.org/msg41114.html [No types assigned]
    Added Reference MITRE https://lists.apache.org/thread.html/r284567dd7523f5823e2ce995f787ccd37b1cc4108779c50a97c79120%40%3Cdev.cloudstack.apache.org%3E [No types assigned]
    Added Reference MITRE https://lists.apache.org/thread.html/r8a58fd7a29808e5d27ee56877745e58dc4bb041b9af94601554e2a5a%40%3Cdev.cloudstack.apache.org%3E [No types assigned]
    Added Reference MITRE https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/A7V2IYO22LWVBGUNZWVKNTMDV4KINLFO/ [No types assigned]
    Added Reference MITRE https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MXTSBY2TEAXWZVFQM3CXHJFRONX7PEMN/ [No types assigned]
    Removed Reference MITRE https://www.mail-archive.com/[email protected]
    Removed Reference MITRE https://www.mail-archive.com/[email protected]/msg41114.html
    Removed Reference MITRE https://lists.apache.org/thread.html/r284567dd7523f5823e2ce995f787ccd37b1cc4108779c50a97c79120@%3Cdev.cloudstack.apache.org%3E
    Removed Reference MITRE https://lists.apache.org/thread.html/r8a58fd7a29808e5d27ee56877745e58dc4bb041b9af94601554e2a5a@%3Cdev.cloudstack.apache.org%3E
    Removed Reference MITRE https://lists.fedoraproject.org/archives/list/[email protected]/message/A7V2IYO22LWVBGUNZWVKNTMDV4KINLFO/
    Removed Reference MITRE https://lists.fedoraproject.org/archives/list/[email protected]/message/MXTSBY2TEAXWZVFQM3CXHJFRONX7PEMN/
  • Modified Analysis by [email protected]

    Dec. 02, 2021

    Action Type Old Value New Value
    Changed Reference Type https://lists.fedoraproject.org/archives/list/[email protected]/message/A7V2IYO22LWVBGUNZWVKNTMDV4KINLFO/ No Types Assigned https://lists.fedoraproject.org/archives/list/[email protected]/message/A7V2IYO22LWVBGUNZWVKNTMDV4KINLFO/ Mailing List, Third Party Advisory
    Changed Reference Type https://lists.fedoraproject.org/archives/list/[email protected]/message/MXTSBY2TEAXWZVFQM3CXHJFRONX7PEMN/ No Types Assigned https://lists.fedoraproject.org/archives/list/[email protected]/message/MXTSBY2TEAXWZVFQM3CXHJFRONX7PEMN/ Mailing List, Third Party Advisory
    Added CPE Configuration OR *cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:* *cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*
  • CVE Modified by [email protected]

    Sep. 17, 2021

    Action Type Old Value New Value
    Added Reference https://lists.fedoraproject.org/archives/list/[email protected]/message/MXTSBY2TEAXWZVFQM3CXHJFRONX7PEMN/ [No Types Assigned]
  • CVE Modified by [email protected]

    Sep. 16, 2021

    Action Type Old Value New Value
    Added Reference https://lists.fedoraproject.org/archives/list/[email protected]/message/A7V2IYO22LWVBGUNZWVKNTMDV4KINLFO/ [No Types Assigned]
  • Initial Analysis by [email protected]

    Sep. 15, 2021

    Action Type Old Value New Value
    Added CVSS V2 NIST (AV:N/AC:L/Au:N/C:N/I:P/A:N)
    Added CVSS V3.1 NIST AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
    Changed Reference Type https://git.haproxy.org/?p=haproxy.git No Types Assigned https://git.haproxy.org/?p=haproxy.git Patch, Vendor Advisory
    Changed Reference Type https://github.com/haproxy/haproxy/commit/3b69886f7dcc3cfb3d166309018e6cfec9ce2c95 No Types Assigned https://github.com/haproxy/haproxy/commit/3b69886f7dcc3cfb3d166309018e6cfec9ce2c95 Patch, Third Party Advisory
    Changed Reference Type https://jfrog.com/blog/critical-vulnerability-in-haproxy-cve-2021-40346-integer-overflow-enables-http-smuggling/ No Types Assigned https://jfrog.com/blog/critical-vulnerability-in-haproxy-cve-2021-40346-integer-overflow-enables-http-smuggling/ Exploit, Mitigation, Third Party Advisory
    Changed Reference Type https://lists.apache.org/thread.html/r284567dd7523f5823e2ce995f787ccd37b1cc4108779c50a97c79120@%3Cdev.cloudstack.apache.org%3E No Types Assigned https://lists.apache.org/thread.html/r284567dd7523f5823e2ce995f787ccd37b1cc4108779c50a97c79120@%3Cdev.cloudstack.apache.org%3E Mailing List, Third Party Advisory
    Changed Reference Type https://lists.apache.org/thread.html/r8a58fd7a29808e5d27ee56877745e58dc4bb041b9af94601554e2a5a@%3Cdev.cloudstack.apache.org%3E No Types Assigned https://lists.apache.org/thread.html/r8a58fd7a29808e5d27ee56877745e58dc4bb041b9af94601554e2a5a@%3Cdev.cloudstack.apache.org%3E Mailing List, Third Party Advisory
    Changed Reference Type https://www.debian.org/security/2021/dsa-4968 No Types Assigned https://www.debian.org/security/2021/dsa-4968 Third Party Advisory
    Changed Reference Type https://www.mail-archive.com/[email protected] No Types Assigned https://www.mail-archive.com/[email protected] Third Party Advisory
    Changed Reference Type https://www.mail-archive.com/[email protected]/msg41114.html No Types Assigned https://www.mail-archive.com/[email protected]/msg41114.html Mitigation, Third Party Advisory
    Added CWE NIST CWE-190
    Added CPE Configuration OR *cpe:2.3:a:haproxy:haproxy:*:*:*:*:*:*:*:* versions from (including) 2.0.0 up to (excluding) 2.0.25 *cpe:2.3:a:haproxy:haproxy:*:*:*:*:*:*:*:* versions from (including) 2.2.0 up to (excluding) 2.2.17 *cpe:2.3:a:haproxy:haproxy:*:*:*:*:*:*:*:* versions from (including) 2.3.0 up to (excluding) 2.3.14 *cpe:2.3:a:haproxy:haproxy:*:*:*:*:*:*:*:* versions from (including) 2.4.0 up to (excluding) 2.4.4 *cpe:2.3:a:haproxy:haproxy:2.5:dev0:*:*:*:*:*:* *cpe:2.3:a:haproxy:haproxy:2.5:dev1:*:*:*:*:*:* *cpe:2.3:a:haproxy:haproxy:2.5:dev2:*:*:*:*:*:* *cpe:2.3:a:haproxy:haproxy:2.5:dev3:*:*:*:*:*:* *cpe:2.3:a:haproxy:haproxy:2.5:dev4:*:*:*:*:*:* *cpe:2.3:a:haproxy:haproxy:2.5:dev5:*:*:*:*:*:* *cpe:2.3:a:haproxy:haproxy:2.5:dev6:*:*:*:*:*:*
    Added CPE Configuration OR *cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*
  • CVE Modified by [email protected]

    Sep. 10, 2021

    Action Type Old Value New Value
    Added Reference https://lists.apache.org/thread.html/r8a58fd7a29808e5d27ee56877745e58dc4bb041b9af94601554e2a5a@%3Cdev.cloudstack.apache.org%3E [No Types Assigned]
  • CVE Modified by [email protected]

    Sep. 10, 2021

    Action Type Old Value New Value
    Added Reference https://lists.apache.org/thread.html/r284567dd7523f5823e2ce995f787ccd37b1cc4108779c50a97c79120@%3Cdev.cloudstack.apache.org%3E [No Types Assigned]
  • CVE Modified by [email protected]

    Sep. 09, 2021

    Action Type Old Value New Value
    Changed Description An integer overflow exists in HAProxy 2.0 through 2.5 in the htx_add_header() 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. 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.
  • CVE Modified by [email protected]

    Sep. 08, 2021

    Action Type Old Value New Value
    Added Reference https://jfrog.com/blog/critical-vulnerability-in-haproxy-cve-2021-40346-integer-overflow-enables-http-smuggling/ [No Types Assigned]
    Added Reference https://github.com/haproxy/haproxy/commit/3b69886f7dcc3cfb3d166309018e6cfec9ce2c95 [No Types Assigned]
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2021-40346 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2021-40346 weaknesses.

Exploit Prediction

EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days.

2.35 }} 0.48%

score

0.89476

percentile

CVSS31 - Vulnerability Scoring System
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality
Integrity
Availability
: