Integer overflow in Haproxy
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.
Vulnerability class: Integer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N.
EPSS exploit prediction
EPSS: 0.588 (99.1th percentile), scored .
High probability of exploitation in the next 30 days — patch promptly. 99th percentile — 99.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.579 · newest: 0.588 · change: +0.009
Affected products
- Haproxy — versions 2.5
- Debian Linux — versions 11.0
- Fedoraproject Fedora — versions 33, 34
Weakness classification (CWE)
Public proof-of-concept exploits
References
- www.mail-archive.com/haproxy@formilux.org
- git.haproxy.org/ (Patch, Vendor Advisory)
- www.debian.org/security/2021/dsa-4968 (vendor-advisory, Third Party Advisory)
- www.mail-archive.com/haproxy@formilux.org/msg41114.html
- jfrog.com/blog/critical-vulnerability-in-haproxy-cve-2021-40346-integer-overflo… (Exploit, Third Party Advisory, Mitigation)
- github.com/haproxy/haproxy/commit/3b69886f7dcc3cfb3d166309018e6cfec9ce2c95 (Patch, Third Party Advisory)
- lists.apache.org/thread.html/r284567dd7523f5823e2ce995f787ccd37b1cc4108779c50a9… (mailing-list)
- lists.apache.org/thread.html/r8a58fd7a29808e5d27ee56877745e58dc4bb041b9af946015… (mailing-list)
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/… (vendor-advisory)
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/… (vendor-advisory)
Frequently asked questions
- What is CVE-2021-40346?
- CVE-2021-40346 is a high-severity vulnerability in Haproxy, classified under Integer Overflow or Wraparound. CVSS score: 7.5/10. Published 2021-09-08.
- How severe is CVE-2021-40346?
- High severity. CVSS v3 base score is 7.5 out of 10.
- Is CVE-2021-40346 known to be exploited?
- 27 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.