Home/CVE/A flaw was found in Open vSwitch. When Open vSwitch is configured with a conntrack flow using FTP helpers over the users
CVE
CVE-2026-34956
A flaw was found in Open vSwitch. When Open vSwitch is configured with a conntrack flow using FTP helpers over the users
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.
MEDIUM · CVSS 5.9
EPSS 0.0014
Monitor
- No active-exploitation, high-EPSS, or public-exploit signals - routine patching cadence
Sigma rules0
YARA rules0
Look this up elsewhere - one-click external pivots
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How to read a CVE - triage first, then detect and patch
This page is every public fact about CVE-2026-34956, cross-linked. Its job is to answer one question fast - does this need my attention now? - and then hand you the two things you do about it. Here is how an analyst reads it.
Triage: should I act now? Four signals, and they are not interchangeable:
CVSSseverity - how bad it is IF exploited, 0-10. A high CVSS alone is not urgency; a flaw can be a perfect 10 and never actually be attacked.
EPSSprobability - a model’s estimate of the chance it is exploited in the next 30 days, 0-1. This is the “will it actually happen” signal.
CISA KEVconfirmed - it is being exploited in the wild right now. The strongest signal on the page; KEV beats any score.
Weaponisedavailability - public exploits / PoCs, and especially Metasploit modules rated Excellent / Great. Reliable, packaged exploit code means low-skill attackers can use it today.
How they combine: KEV, or a dependable Metasploit module, means patch now regardless of CVSS. High CVSS + low EPSS + no exploit is real but not an emergency - schedule it. Low CVSS but KEV-listed still gets patched now. The verdict above already weighed these for you; this is how it got there.
Then what - two workflows:
Detectwhen you cannot patch today, follow this CVE to the ATT&CK techniques it enables, then Build a SIEM detection (the green button) - author a rule, test it in Atomic, deploy it. That buys visibility while the patch waits.
PatchAffected products / packages tell you if you are exposed; Fixed versions by distribution and Vendor advisories give the exact version that closes it.
Reading order for the panels below: verdict + badges, then Public exploits / Metasploit (is it weaponised), then ATT&CK techniques + Sigma / IDS rules (can I detect it), then Affected products / packages + Fixed versions (am I exposed, what patches it), then Threat actors / IOCs (who uses it), then Scoring & timeline / references (the evidence).
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ATT&CK techniques
1Techniques this CVE enables - linked via CWECAPECATT&CK. High◆ = named directly in ATT&CK or Nuclei templates.
▤ Build a SIEM detection for these techniques▤
CAPEC attack patterns
12Attack patterns this CVE enables - the bridge from weakness to ATT&CK technique.
CAPEC-CAPEC-10 · Buffer Overflow via Environment Variables CAPEC-CAPEC-100 · Overflow Buffers CAPEC-CAPEC-14 · Client-side Injection-induced Buffer Overflow CAPEC-CAPEC-24 · Filter Failure through Buffer Overflow CAPEC-CAPEC-42 · MIME Conversion CAPEC-CAPEC-44 · Overflow Binary Resource File CAPEC-CAPEC-45 · Buffer Overflow via Symbolic Links CAPEC-CAPEC-46 · Overflow Variables and Tags CAPEC-CAPEC-47 · Buffer Overflow via Parameter Expansion CAPEC-CAPEC-67 · String Format Overflow in syslog() CAPEC-CAPEC-8 · Buffer Overflow in an API Call CAPEC-CAPEC-9 · Buffer Overflow in Local Command-Line Utilities
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Weakness Classification
📦
Fixed versions by distribution
18The package version that resolves this CVE on each Linux distribution, from the vendor’s published security data. fixed in shows a patched version exists; open means the package is listed as affected with no fix yet.
suse sle15libopenvswitch-2_14-0 fixed in 0:2.14.2-150400.24.32.1
suse sle15libopenvswitch-3_5-0 fixed in 0:3.5.4-150700.41.15.1
suse sle15libovn-20_06-0 fixed in 0:20.06.2-150400.24.32.1
suse sle15libovn-25_03-0 fixed in 0:25.03.2-150700.41.15.1
suse sle15openvswitch fixed in 0:3.5.4-150700.41.15.1
suse sle15openvswitch-devel fixed in 0:3.5.4-150700.41.15.1
suse sle15openvswitch-ipsec fixed in 0:2.14.2-150400.24.32.1
suse sle15openvswitch-pki fixed in 0:3.5.4-150700.41.15.1
suse sle15openvswitch-test fixed in 0:2.14.2-150400.24.32.1
suse sle15openvswitch-vtep fixed in 0:2.14.2-150400.24.32.1
suse sle15ovn fixed in 0:20.06.2-150400.24.32.1
suse sle15ovn-central fixed in 0:25.03.2-150700.41.15.1
suse sle15ovn-devel fixed in 0:25.03.2-150700.41.15.1
suse sle15ovn-docker fixed in 0:20.06.2-150400.24.32.1
suse sle15ovn-host fixed in 0:25.03.2-150700.41.15.1
suse sle15ovn-vtep fixed in 0:25.03.2-150700.41.15.1
suse sle15python3-openvswitch fixed in 0:3.5.4-150700.41.15.1
suse sle15python3-ovs fixed in 0:2.14.2-150400.24.32.1
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Scoring & Timeline
5.9
MEDIUM · CVSS v3.1 · [email protected]
Attack Vector
Network
Adjacent
Local
Physical
Attack Complexity
Low
High
Privileges Required
None
Low
High
User Interaction
None
Required
Scope
Unchanged
Changed
Confidentiality
None
Low
High
Integrity
None
Low
High
Availability
None
Low
High
SSVC triage · cisa-vulnrichment
Exploitation
none
Automatable
no
Technical impact
partial
SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.
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Vendor Advisories
7suse-csafSUSE-SU-2026:22068-1
msrcCVE-2026-34956
suse-csafSUSE-SU-2026:21250-1
suse-csafSUSE-SU-2026:1482-1
suse-csafSUSE-SU-2026:1439-1
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References & Sources
3Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.