{"id":"CVE-2026-34956","title":"A flaw was found in Open vSwitch","summary":"A flaw was found in Open vSwitch. When Open vSwitch is configured with a conntrack flow using FTP helpers over the userspace datapath, a remote attacker can send a specially crafted FTP stream with an EPASV command exceeding 255 characte…","severity":"medium","cvss":5.9,"cvssVector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","cwe":["CWE-120"],"published":"2026-05-05","updated":"2026-08-21","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-34956","references":[{"url":"https://access.redhat.com/security/cve/CVE-2026-34956","label":"secalert@redhat.com"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2453459","label":"secalert@redhat.com"},{"url":"http://www.openwall.com/lists/oss-security/2026/03/31/15","label":"af854a3a-2127-422b-91ae-364da2661108"}],"tags":["nvd"],"epss":0.00405,"epssPercentile":0.34579,"ingestedAt":"2026-08-22T01:24:51.197Z","slug":"CVE-2026-34956","body":"## Overview\n\nA flaw was found in Open vSwitch. When Open vSwitch is configured with a conntrack flow using FTP helpers over the userspace datapath, a remote attacker can send a specially crafted FTP stream with an EPASV command exceeding 255 characters. This heap access error can lead to a crash, resulting in a Denial of Service (DoS) for the affected system.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":33,"depthScoreParts":{"impact":32.5,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}