FKIE_CVE-2026-34956
Vulnerability from fkie_nvd - Published: 2026-05-05 16:16 - Updated: 2026-09-01 13:18
Severity
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 characters. This heap access error can lead to a crash, resulting in a Denial of Service (DoS) for the affected system.
References
Impacted products
| Vendor | Product | Version |
|---|
{
"affected": [
{
"affectedData": [
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/o:redhat:enterprise_linux:7::fastdatapath"
],
"defaultStatus": "affected",
"packageName": "openvswitch",
"product": "Fast Datapath for RHEL 7",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/o:redhat:enterprise_linux:7::fastdatapath"
],
"defaultStatus": "affected",
"packageName": "openvswitch2.10",
"product": "Fast Datapath for RHEL 7",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/o:redhat:enterprise_linux:7::fastdatapath"
],
"defaultStatus": "affected",
"packageName": "openvswitch2.11",
"product": "Fast Datapath for RHEL 7",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/o:redhat:enterprise_linux:7::fastdatapath"
],
"defaultStatus": "affected",
"packageName": "openvswitch2.12",
"product": "Fast Datapath for RHEL 7",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/o:redhat:enterprise_linux:7::fastdatapath"
],
"defaultStatus": "affected",
"packageName": "openvswitch2.13",
"product": "Fast Datapath for RHEL 7",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/o:redhat:enterprise_linux:7::fastdatapath"
],
"defaultStatus": "affected",
"packageName": "openvswitch-selinux-extra-policy",
"product": "Fast Datapath for RHEL 7",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/o:redhat:enterprise_linux:7::fastdatapath"
],
"defaultStatus": "affected",
"packageName": "ovn2.11",
"product": "Fast Datapath for RHEL 7",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/o:redhat:enterprise_linux:7::fastdatapath"
],
"defaultStatus": "affected",
"packageName": "ovn2.12",
"product": "Fast Datapath for RHEL 7",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/o:redhat:enterprise_linux:8::fastdatapath"
],
"defaultStatus": "affected",
"packageName": "openvswitch2.11",
"product": "Fast Datapath for RHEL 8",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/o:redhat:enterprise_linux:8::fastdatapath"
],
"defaultStatus": "affected",
"packageName": "openvswitch2.12",
"product": "Fast Datapath for RHEL 8",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/o:redhat:enterprise_linux:8::fastdatapath"
],
"defaultStatus": "affected",
"packageName": "openvswitch2.13",
"product": "Fast Datapath for RHEL 8",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/o:redhat:enterprise_linux:8::fastdatapath"
],
"defaultStatus": "affected",
"packageName": "openvswitch2.15",
"product": "Fast Datapath for RHEL 8",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/o:redhat:enterprise_linux:8::fastdatapath"
],
"defaultStatus": "affected",
"packageName": "openvswitch2.16",
"product": "Fast Datapath for RHEL 8",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/o:redhat:enterprise_linux:8::fastdatapath"
],
"defaultStatus": "affected",
"packageName": "openvswitch2.17",
"product": "Fast Datapath for RHEL 8",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/o:redhat:enterprise_linux:8::fastdatapath"
],
"defaultStatus": "affected",
"packageName": "openvswitch3.1",
"product": "Fast Datapath for RHEL 8",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/o:redhat:enterprise_linux:8::fastdatapath"
],
"defaultStatus": "affected",
"packageName": "openvswitch-selinux-extra-policy",
"product": "Fast Datapath for RHEL 8",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/o:redhat:enterprise_linux:8::fastdatapath"
],
"defaultStatus": "affected",
"packageName": "ovn2.11",
"product": "Fast Datapath for RHEL 8",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/o:redhat:enterprise_linux:8::fastdatapath"
],
"defaultStatus": "affected",
"packageName": "ovn2.12",
"product": "Fast Datapath for RHEL 8",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/o:redhat:enterprise_linux:9::fastdatapath"
],
"defaultStatus": "affected",
"packageName": "openvswitch2.17",
"product": "Fast Datapath for RHEL 9",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/o:redhat:enterprise_linux:9::fastdatapath"
],
"defaultStatus": "affected",
"packageName": "openvswitch3.0",
"product": "Fast Datapath for RHEL 9",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/o:redhat:enterprise_linux:9::fastdatapath"
],
"defaultStatus": "affected",
"packageName": "openvswitch3.1",
"product": "Fast Datapath for RHEL 9",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/o:redhat:enterprise_linux:9::fastdatapath"
],
"defaultStatus": "affected",
"packageName": "openvswitch3.2",
"product": "Fast Datapath for RHEL 9",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/o:redhat:enterprise_linux:9::fastdatapath"
],
"defaultStatus": "affected",
"packageName": "openvswitch3.3",
"product": "Fast Datapath for RHEL 9",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/o:redhat:enterprise_linux:9::fastdatapath"
],
"defaultStatus": "affected",
"packageName": "openvswitch3.4",
"product": "Fast Datapath for RHEL 9",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/o:redhat:enterprise_linux:9::fastdatapath"
],
"defaultStatus": "affected",
"packageName": "openvswitch3.5",
"product": "Fast Datapath for RHEL 9",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/o:redhat:enterprise_linux:9::fastdatapath"
],
"defaultStatus": "affected",
"packageName": "openvswitch3.6",
"product": "Fast Datapath for RHEL 9",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/o:redhat:enterprise_linux:9::fastdatapath"
],
"defaultStatus": "affected",
"packageName": "openvswitch-selinux-extra-policy",
"product": "Fast Datapath for RHEL 9",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/o:redhat:enterprise_linux:7"
],
"defaultStatus": "affected",
"packageName": "openvswitch",
"product": "Red Hat Enterprise Linux 7",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/a:redhat:openshift:4"
],
"defaultStatus": "affected",
"packageName": "openshift/ose-rhel-coreos-8",
"product": "Red Hat OpenShift Container Platform 4",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/a:redhat:openshift:4"
],
"defaultStatus": "affected",
"packageName": "openshift/ose-rhel-coreos-9",
"product": "Red Hat OpenShift Container Platform 4",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/a:redhat:openshift:4"
],
"defaultStatus": "affected",
"packageName": "openvswitch2.17",
"product": "Red Hat OpenShift Container Platform 4",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/a:redhat:openshift:4"
],
"defaultStatus": "affected",
"packageName": "openvswitch3.0",
"product": "Red Hat OpenShift Container Platform 4",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/a:redhat:openshift:4"
],
"defaultStatus": "affected",
"packageName": "openvswitch3.1",
"product": "Red Hat OpenShift Container Platform 4",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/a:redhat:openstack:13"
],
"defaultStatus": "affected",
"packageName": "rhosp13/openstack-neutron-openvswitch-agent",
"product": "Red Hat OpenStack Platform 13 (Queens)",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/a:redhat:openstack:13"
],
"defaultStatus": "affected",
"packageName": "rhosp13/openstack-openvswitch-base",
"product": "Red Hat OpenStack Platform 13 (Queens)",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/a:redhat:openstack:13"
],
"defaultStatus": "affected",
"packageName": "rhosp13/openstack-ovn-base",
"product": "Red Hat OpenStack Platform 13 (Queens)",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/a:redhat:openstack:16.2"
],
"defaultStatus": "affected",
"packageName": "rhosp-openvswitch",
"product": "Red Hat OpenStack Platform 16.2",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/a:redhat:openstack:16.2"
],
"defaultStatus": "affected",
"packageName": "rhosp-rhel8/openstack-neutron-openvswitch-agent",
"product": "Red Hat OpenStack Platform 16.2",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/a:redhat:openstack:17.1"
],
"defaultStatus": "affected",
"packageName": "rhosp-openvswitch",
"product": "Red Hat OpenStack Platform 17.1",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/a:redhat:openstack:17.1"
],
"defaultStatus": "affected",
"packageName": "rhosp-rhel9/openstack-neutron-openvswitch-agent",
"product": "Red Hat OpenStack Platform 17.1",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/a:redhat:openstack:18.0"
],
"defaultStatus": "affected",
"packageName": "rhoso-openvswitch",
"product": "Red Hat OpenStack Platform 18.0",
"vendor": "Red Hat"
}
],
"source": "secalert@redhat.com"
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "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."
}
],
"id": "CVE-2026-34956",
"lastModified": "2026-09-01T13:18:58.630",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "HIGH",
"attackVector": "NETWORK",
"availabilityImpact": "HIGH",
"baseScore": 5.9,
"baseSeverity": "MEDIUM",
"confidentialityImpact": "NONE",
"integrityImpact": "NONE",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H",
"version": "3.1"
},
"exploitabilityScore": 2.2,
"impactScore": 3.6,
"source": "secalert@redhat.com",
"type": "Secondary"
}
],
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2026-34956",
"options": [
{
"exploitation": "none"
},
{
"automatable": "no"
},
{
"technicalImpact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-05-06T14:17:23.457705Z",
"version": "2.0.3"
}
}
]
},
"published": "2026-05-05T16:16:11.927",
"references": [
{
"source": "secalert@redhat.com",
"url": "https://access.redhat.com/security/cve/CVE-2026-34956"
},
{
"source": "secalert@redhat.com",
"url": "https://bugzilla.redhat.com/show_bug.cgi?id=2453459"
},
{
"source": "af854a3a-2127-422b-91ae-364da2661108",
"url": "http://www.openwall.com/lists/oss-security/2026/03/31/15"
}
],
"sourceIdentifier": "secalert@redhat.com",
"vulnStatus": "Awaiting Analysis",
"weaknesses": [
{
"description": [
{
"lang": "en",
"value": "CWE-120"
}
],
"source": "secalert@redhat.com",
"type": "Secondary"
}
]
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.
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