CVE-2021-39240
An issue was discovered in HAProxy 2.2 before 2.2.16, 2.3 before 2.3.13, and 2.4 before 2.4.3.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (2.21%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
An issue was discovered in HAProxy 2.2 before 2.2.16, 2.3 before 2.3.13, and 2.4 before 2.4.3. It does not ensure that the scheme and path portions of a URI have the expected characters. For example, the authority field (as observed on a target HTTP/2 server) might differ from what the routing rules were intended to achieve.
- CVSS 3.1
- 7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
- EPSS
- 2.21% probability · 82th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Affected
- haproxy/haproxy · debian/debian linux · fedoraproject/fedora
- Source
- cve@mitre.org
EPSS 2.2% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://git.haproxy.org/?p=haproxy.git%3Ba=commit%3Bh=4b8852c70d8c4b7e225e24eb58258a15eb54c26e
- https://git.haproxy.org/?p=haproxy.git%3Ba=commit%3Bh=a495e0d94876c9d39763db319f609351907a31e8
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4ALECUZDIMT5FYGP6V6PVSI4BKVZTZWN/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RPNY4WZIQUAUOCLIMUPC37AQWNXTWIQM/
- https://www.debian.org/security/2021/dsa-4960Third Party Advisory
- https://www.mail-archive.com/haproxy%40formilux.org/msg41041.html
- https://git.haproxy.org/?p=haproxy.git%3Ba=commit%3Bh=4b8852c70d8c4b7e225e24eb58258a15eb54c26e
- https://git.haproxy.org/?p=haproxy.git%3Ba=commit%3Bh=a495e0d94876c9d39763db319f609351907a31e8
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4ALECUZDIMT5FYGP6V6PVSI4BKVZTZWN/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RPNY4WZIQUAUOCLIMUPC37AQWNXTWIQM/
- https://www.debian.org/security/2021/dsa-4960Third Party Advisory
- https://www.mail-archive.com/haproxy%40formilux.org/msg41041.html
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.