Buffer overflow in Red Hat Fast Datapath For Rhel 7
CVE-2026-34956
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 characters. This heap access error can lead to a crash, resulting in a Denial of Service (DoS) for the affected system.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.9 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.006 (49.8th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 50th percentile — 49.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.006 · newest: 0.006 · change: 0.000
Affected products
Weakness classification (CWE)
References
- access.redhat.com/security/cve/CVE-2026-34956 (vdb-entry)
- bugzilla.redhat.com/show_bug.cgi (issue-tracking)
- af854a3a-2127-422b-91ae-364da2661108
Frequently asked questions
- What is CVE-2026-34956?
- CVE-2026-34956 is a medium-severity vulnerability in Red Hat Fast Datapath For Rhel 7, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 5.9/10. Published 2026-05-05.
- How severe is CVE-2026-34956?
- Medium severity. CVSS v3 base score is 5.9 out of 10.