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NVD / CVE Program· CNA Linux

CVE-2026-31678: openvswitch: defer tunnel netdev_put to RCU release

HighCVSS 7.8 · v3.1—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 31/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.13% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 42f0d3d81209654c08ffdde5a34b9b92d2645896, 6931d21f87bc6d657f145798fad0bf077b82486c, 98b726ab5e2a4811e27c28e4d041f75bba147eab; azl3 kernel 6.6.130.1-3 on Azure Linux 3.0 6.6.134.1-2.

Low priority for now. Upgrade to Linux Linux 42f0d3d81209654c08ffdde5a34b9b92d2645896, 6931d21f87bc6d657f145798fad0bf077b82486c, 98b726ab5e2a4811e27c28e4d041f75bba147eab; azl3 kernel 6.6.130.1-3 on Azure Linux 3.0 6.6.134.1-2 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

In the Linux kernel, the following vulnerability has been resolved: openvswitch: defer tunnel netdev_put to RCU release ovs_netdev_tunnel_destroy() may run after NETDEV_UNREGISTER already detached the device. Dropping the netdev reference in destroy can race with concurrent readers that still observe vport->dev. Do not release vport->dev in ovs_netdev_tunnel_destroy(). Instead, let vport_netdev_free() drop the reference from the RCU callback, matching the non-tunnel destroy path and avoiding additional synchronization under RTNL.

Published
Apr 25, 2026
Updated
Nov 11, 2026
EPSS
0.1% · 2th percentile

Report tools

JSON

Action score

31

Monitor

Low priority for now.

CVSS
31 / 40 · 7.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · Linux
7.8
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

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  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

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Follow CVE-2026-31678

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
linuxlinux kernel

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 4.3affected
    • a9020fde67a6eb77f8130feff633189f99264db1 and later · before f0ec49d3a39c1f5a4f3270ea27ca0854fad2a2a2affected · git
    • a9020fde67a6eb77f8130feff633189f99264db1 and later · before 9d56aced21fb9c104e8a3f3be9b21fbafe448ffcaffected · git
    • a9020fde67a6eb77f8130feff633189f99264db1 and later · before 42f0d3d81209654c08ffdde5a34b9b92d2645896affected · git
    • a9020fde67a6eb77f8130feff633189f99264db1 and later · before bbe7bd722bfaea36aab3da6cc60fb4a05c644643affected · git
    • a9020fde67a6eb77f8130feff633189f99264db1 and later · before 98b726ab5e2a4811e27c28e4d041f75bba147eabaffected · git
    • a9020fde67a6eb77f8130feff633189f99264db1 and later · before b8c56a3fc5d879c0928f207a756b0f067f06c6a8affected · git
    • a9020fde67a6eb77f8130feff633189f99264db1 and later · before 6931d21f87bc6d657f145798fad0bf077b82486caffected · git
    • before 4.3not affected · semver
    • 5.15.224 and later · up to and including 5.15.*not affected · semver
Affected versions · NVD (6)

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernel4.3 and later · before 6.1.168
  • linux linux kernel6.2 and later · before 6.6.131
  • linux linux kernel6.7 and later · before 6.12.80
  • linux linux kernel6.13 and later · before 6.18.21
  • linux linux kernel6.19 and later · before 6.19.11
  • linux linux kernel7.0

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
AlmaLinux:10kernelbefore 6.12.0-211.67.1.el10_26.12.0-211.67.1.el10_2
AlmaLinux:10kernel-64kbefore 6.12.0-211.67.1.el10_26.12.0-211.67.1.el10_2
AlmaLinux:10kernel-64k-corebefore 6.12.0-211.67.1.el10_26.12.0-211.67.1.el10_2
AlmaLinux:10kernel-64k-debugbefore 6.12.0-211.67.1.el10_26.12.0-211.67.1.el10_2
AlmaLinux:10kernel-64k-debug-corebefore 6.12.0-211.67.1.el10_26.12.0-211.67.1.el10_2
AlmaLinux:10kernel-64k-debug-develbefore 6.12.0-211.67.1.el10_26.12.0-211.67.1.el10_2
AlmaLinux:10kernel-64k-debug-devel-matchedbefore 6.12.0-211.67.1.el10_26.12.0-211.67.1.el10_2
AlmaLinux:10kernel-64k-debug-modulesbefore 6.12.0-211.67.1.el10_26.12.0-211.67.1.el10_2
AlmaLinux:10kernel-64k-debug-modules-corebefore 6.12.0-211.67.1.el10_26.12.0-211.67.1.el10_2
AlmaLinux:10kernel-64k-debug-modules-extrabefore 6.12.0-211.67.1.el10_26.12.0-211.67.1.el10_2
AlmaLinux:10kernel-64k-develbefore 6.12.0-211.67.1.el10_26.12.0-211.67.1.el10_2
AlmaLinux:10kernel-64k-devel-matchedbefore 6.12.0-211.67.1.el10_26.12.0-211.67.1.el10_2
AlmaLinux:10kernel-64k-modulesbefore 6.12.0-211.67.1.el10_26.12.0-211.67.1.el10_2
AlmaLinux:10kernel-64k-modules-corebefore 6.12.0-211.67.1.el10_26.12.0-211.67.1.el10_2
AlmaLinux:10kernel-64k-modules-extrabefore 6.12.0-211.67.1.el10_26.12.0-211.67.1.el10_2
AlmaLinux:10kernel-abi-stablelistsbefore 6.12.0-211.67.1.el10_26.12.0-211.67.1.el10_2
AlmaLinux:10kernel-corebefore 6.12.0-211.67.1.el10_26.12.0-211.67.1.el10_2
AlmaLinux:10kernel-cross-headersbefore 6.12.0-211.67.1.el10_26.12.0-211.67.1.el10_2
AlmaLinux:10kernel-debugbefore 6.12.0-211.67.1.el10_26.12.0-211.67.1.el10_2
AlmaLinux:10kernel-debug-corebefore 6.12.0-211.67.1.el10_26.12.0-211.67.1.el10_2
AlmaLinux:10kernel-debug-develbefore 6.12.0-211.67.1.el10_26.12.0-211.67.1.el10_2
AlmaLinux:10kernel-debug-devel-matchedbefore 6.12.0-211.67.1.el10_26.12.0-211.67.1.el10_2
AlmaLinux:10kernel-debug-modulesbefore 6.12.0-211.67.1.el10_26.12.0-211.67.1.el10_2
AlmaLinux:10kernel-debug-modules-corebefore 6.12.0-211.67.1.el10_26.12.0-211.67.1.el10_2

+96

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
    90Now
  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe…KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now

Published before and after this one in the same product

  • ← EarlierCVE-2026-31676Apr 25, 2026 · rxrpc: only handle RESPONSE during service challenge
    30Monitor
  • ← EarlierCVE-2026-31677Apr 25, 2026 · crypto: af_alg - limit RX SG extraction by receive buffer budget
    22Monitor
  • Later →CVE-2026-31679Apr 25, 2026 · openvswitch: validate MPLS set/set_masked payload length
    28Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux42f0d3d81209654c08ffdde5a34b9b92d2645896Vendor (CNA)
Linux Linux6931d21f87bc6d657f145798fad0bf077b82486cVendor (CNA)
Linux Linux98b726ab5e2a4811e27c28e4d041f75bba147eabVendor (CNA)
Linux Linux9d56aced21fb9c104e8a3f3be9b21fbafe448ffcVendor (CNA)
Linux Linuxb8c56a3fc5d879c0928f207a756b0f067f06c6a8Vendor (CNA)
Linux Linuxbbe7bd722bfaea36aab3da6cc60fb4a05c644643Vendor (CNA)
Linux Linuxf0ec49d3a39c1f5a4f3270ea27ca0854fad2a2a2Vendor (CNA)
azl3 kernel 6.6.130.1-3 on Azure Linux 3.06.6.134.1-2 · CBL-Mariner ReleasesMicrosoft (MSRC)
almalinux:bpftool4.18.0-553.173.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel4.18.0-553.173.1.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-rt4.18.0-553.173.1.rt7.514.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-rt-core4.18.0-553.173.1.rt7.514.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-rt-debug4.18.0-553.173.1.rt7.514.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-rt-debug-core4.18.0-553.173.1.rt7.514.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-rt-debug-devel4.18.0-553.173.1.rt7.514.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-rt-debug-modules4.18.0-553.173.1.rt7.514.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-rt-debug-modules-extra4.18.0-553.173.1.rt7.514.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-rt-devel4.18.0-553.173.1.rt7.514.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-rt-modules4.18.0-553.173.1.rt7.514.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:kernel-rt-modules-extra4.18.0-553.173.1.rt7.514.el8_10 · AlmaLinux:8Package registry (OSV)
debian:linux6.1.170-1 · Debian:12Package registry (OSV)
red hat:kernel-rt0:4.18.0-553.173.1.rt7.514.el8_10 · Red Hat:enterprise_linux:8::nfvPackage registry (OSV)
red hat:kernel-rt-core0:4.18.0-553.173.1.rt7.514.el8_10 · Red Hat:enterprise_linux:8::nfvPackage registry (OSV)
red hat:kernel-rt-debug0:4.18.0-553.173.1.rt7.514.el8_10 · Red Hat:enterprise_linux:8::nfvPackage registry (OSV)
red hat:kernel-rt-debug-core0:4.18.0-553.173.1.rt7.514.el8_10 · Red Hat:enterprise_linux:8::nfvPackage registry (OSV)
red hat:kernel-rt-debug-debuginfo0:4.18.0-553.173.1.rt7.514.el8_10 · Red Hat:enterprise_linux:8::nfvPackage registry (OSV)
red hat:kernel-rt-debug-devel0:4.18.0-553.173.1.rt7.514.el8_10 · Red Hat:enterprise_linux:8::nfvPackage registry (OSV)
red hat:kernel-rt-debug-kvm0:4.18.0-553.173.1.rt7.514.el8_10 · Red Hat:enterprise_linux:8::nfvPackage registry (OSV)
red hat:kernel-rt-debug-modules0:4.18.0-553.173.1.rt7.514.el8_10 · Red Hat:enterprise_linux:8::nfvPackage registry (OSV)
red hat:kernel-rt-debug-modules-extra0:4.18.0-553.173.1.rt7.514.el8_10 · Red Hat:enterprise_linux:8::nfvPackage registry (OSV)

+9

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2025-38352277 days apartposix-cpu-timers: fix race between handle_posix_cpu_timers() and posix_cpu_timer_del()KEV
    61This week
  • CVE-2026-6409185 days apartbatman-adv: tt: fix TOCTOU race for reported vlans
    39Monitor
  • CVE-2026-6403485 days apartnet: mana: Fix TOCTOU double-fetch of hwc_msg_id from DMA buffer
    37Monitor
  • CVE-2026-6393785 days apartKVM: SEV: Use READ_ONCE() when reading entries/indices from PSC buffer
    35Monitor
  • CVE-2026-6386785 days apartmptcp: close TOCTOU race while computing rcv_wnd
    32Monitor
  • CVE-2026-4343313 days apartrust_binder: avoid reading the written value in offsets array
    31Monitor

Not on record for this CVE: EPSS history · patch commit or PR link · researcher credit · public bounty program.

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-367 · Time-of-check Time-of-use (TOCTOU) Race Condition

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

References

Show all references (6 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records