CVE-2021-40346

Exploitation

Not assessed. CISA has not published an exploitation assessment for this record, and it is not in the KEV catalog. That is an absence of assessment, not a finding of no risk.

SSVC decision

Not assessed by CISA

EPSS probability

58.83% probability of exploitation activity in the next 30 days.

EPSS percentile

Equal to or higher than the score of 99.0% of scored records. A rank, not a probability.

NVD base score

7.5 (CVSS v3.x), scored by the NVD independently of the CNA.

NVD CVSS vector

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

NVD analysis status

Modified. NVD last modified this record on 2026-06-17.

Red Hat severity

Moderate. Red Hat's rating for its own products, not a CVSS rating.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

Published

2021-09-08 16:40Z5 YR AGO

Last updated

2024-08-04 02:27Z2 YR AGO

Reserved

2021-08-31

Assigning CNA

mitre

Record state

PUBLISHED

Severity

Not rated by the issuing CNA

CNA CVSS vector

Not published by the issuing CNA

Weaknesses

• CWE-190Integer Overflow or WraparoundBase
• CWE-444Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')Base

Data version

5.1

Document digest

847be360698696009fd4542bfa525516f616201a0a760ff602c304f102370fe9

• www.mail-archive.comhttps://www.mail-archive.com/haproxy%40formilux.orgx_refsource_MISC
• git.haproxy.orghttps://git.haproxy.org/?p=haproxy.gitx_refsource_MISC
• www.debian.orgDSA-4968https://www.debian.org/security/2021/dsa-4968vendor-advisoryx_refsource_DEBIAN
• www.mail-archive.comhttps://www.mail-archive.com/haproxy%40formilux.org/msg41114.htmlx_refsource_MISC
• jfrog.comhttps://jfrog.com/blog/critical-vulnerability-in-haproxy-cve-2021-40346-integer-overflow-enables-http-smuggling/x_refsource_MISC
• github.comhttps://github.com/haproxy/haproxy/commit/3b69886f7dcc3cfb3d166309018e6cfec9ce2c95x_refsource_MISC
• lists.apache.org[cloudstack-dev] 20210910 CVE-2021-40346 (haproxy 2.x)https://lists.apache.org/thread.html/r284567dd7523f5823e2ce995f787ccd37b1cc4108779c50a97c79120%40%3Cdev.cloudstack.apache.org%3Emailing-listx_refsource_MLIST
• lists.apache.org[cloudstack-dev] 20210910 Re: CVE-2021-40346 (haproxy 2.x)https://lists.apache.org/thread.html/r8a58fd7a29808e5d27ee56877745e58dc4bb041b9af94601554e2a5a%40%3Cdev.cloudstack.apache.org%3Emailing-listx_refsource_MLIST
• lists.fedoraproject.orgFEDORA-2021-3493f9f6abhttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/A7V2IYO22LWVBGUNZWVKNTMDV4KINLFO/vendor-advisoryx_refsource_FEDORA
• lists.fedoraproject.orgFEDORA-2021-cd5ee418f6https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MXTSBY2TEAXWZVFQM3CXHJFRONX7PEMN/vendor-advisoryx_refsource_FEDORA