{"id":"CVE-2021-39240","url":"https://www.cyber-defence.io/tools/cve/CVE-2021-39240","generatedAt":"2026-10-27T19:57:38.752Z","title":"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.","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.","published":"2021-08-17T19:15:08.000Z","lastModified":"2026-06-17T04:03:23.000Z","status":"Modified","sourceIdentifier":"cve@mitre.org","cvss":{"version":"3.1","score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N"},"cwe":[],"affected":["haproxy/haproxy","debian/debian linux","fedoraproject/fedora"],"epss":{"score":0.0221,"percentile":0.82475,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"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."},"changes":[],"references":[{"url":"https://git.haproxy.org/?p=haproxy.git%3Ba=commit%3Bh=4b8852c70d8c4b7e225e24eb58258a15eb54c26e","source":"cve@mitre.org"},{"url":"https://git.haproxy.org/?p=haproxy.git%3Ba=commit%3Bh=a495e0d94876c9d39763db319f609351907a31e8","source":"cve@mitre.org"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4ALECUZDIMT5FYGP6V6PVSI4BKVZTZWN/","source":"cve@mitre.org"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RPNY4WZIQUAUOCLIMUPC37AQWNXTWIQM/","source":"cve@mitre.org"},{"url":"https://www.debian.org/security/2021/dsa-4960","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://www.mail-archive.com/haproxy%40formilux.org/msg41041.html","source":"cve@mitre.org"},{"url":"https://git.haproxy.org/?p=haproxy.git%3Ba=commit%3Bh=4b8852c70d8c4b7e225e24eb58258a15eb54c26e","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://git.haproxy.org/?p=haproxy.git%3Ba=commit%3Bh=a495e0d94876c9d39763db319f609351907a31e8","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4ALECUZDIMT5FYGP6V6PVSI4BKVZTZWN/","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RPNY4WZIQUAUOCLIMUPC37AQWNXTWIQM/","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.debian.org/security/2021/dsa-4960","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.mail-archive.com/haproxy%40formilux.org/msg41041.html","source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2021-39240","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}