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NVD / CVE Program· CNA Linux

CVE-2026-23381: net: bridge: fix nd_tbl NULL dereference when IPv6 is disabled

Noroxi assessment

Priority: Monitor (action score 22/100)

  • 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: 0.12% (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 20ef5c25422f97dd09d751e5ae6c18406cdc78e6, 33dec6f10777d5a8f71c0a200f690da5ae3c2e55, 7a894eb5de246d79f13105c55a67381039a24d44; azl3 kernel 6.6.126.1-1 on Azure Linux 3.0 6.6.130.1-1; cbl2 kernel 5.15.202.1-1 on CBL-Mariner 2.0 Release Notes.

Low priority for now. Upgrade to Linux Linux 20ef5c25422f97dd09d751e5ae6c18406cdc78e6, 33dec6f10777d5a8f71c0a200f690da5ae3c2e55, 7a894eb5de246d79f13105c55a67381039a24d44; azl3 kernel 6.6.126.1-1 on Azure Linux 3.0 6.6.130.1-1; cbl2 kernel 5.15.202.1-1 on CBL-Mariner 2.0 Release Notes 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: net: bridge: fix nd_tbl NULL dereference when IPv6 is disabled When booting with the 'ipv6.disable=1' parameter, the nd_tbl is never initialized because inet6_init() exits before ndisc_init() is called which initializes it. Then, if neigh_suppress is enabled and an ICMPv6 Neighbor Discovery packet reaches the bridge, br_do_suppress_nd() will dereference ipv6_stub->nd_tbl which is NULL, passing it to neigh_lookup(). This causes a kernel NULL pointer dereference. BUG: kernel NULL pointer dereference, address: 0000000000000268 Oops: 0000 [#1] PREEMPT SMP NOPTI [...] RIP: 0010:neigh_lookup+0x16/0xe0 [...] Call Trace: <IRQ> ? neigh_lookup+0x16/0xe0 br_do_suppress_nd+0x160/0x290 [bridge] br_handle_frame_finish+0x500/0x620 [bridge] br_handle_frame+0x353/0x440 [bridge] __netif_receive_skb_core.constprop.0+0x298/0x1110 __netif_receive_skb_one_core+0x3d/0xa0 process_backlog+0xa0/0x140 __napi_poll+0x2c/0x170 net_rx_action+0x2c4/0x3a0 handle_softirqs+0xd0/0x270 do_softirq+0x3f/0x60 Fix this by replacing IS_ENABLED(IPV6) call with ipv6_mod_enabled() in the callers. This is in essence disabling NS/NA suppression when IPv6 is disabled.

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
Mar 25, 2026
Updated
Nov 5, 2026
EPSS
0.1% · 2th percentile

Report tools

JSON

Action score

22

Monitor

Low priority for now.

CVSS
22 / 40 · 5.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

Get told when this record changes

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

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-23381

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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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

Affected versions

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

  • linux linux kernel4.15.1 and later · before 5.10.253
  • linux linux kernel5.11 and later · before 5.15.203
  • linux linux kernel5.16 and later · before 6.1.167
  • linux linux kernel6.2 and later · before 6.6.130
  • linux linux kernel6.7 and later · before 6.12.77
  • linux linux kernel6.13 and later · before 6.18.17
  • linux linux kernel6.19 and later · before 6.19.7
  • linux linux kernel4.15
  • linux linux kernel7.0

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

    • 4.15affected
    • ed842faeb2bd49256f00485402f3113205f91d30 and later · before a9d712ccfeef737c0e700a4b5b98f310e07b6b60affected · git
    • ed842faeb2bd49256f00485402f3113205f91d30 and later · before a5c56e65b685360dd3f2278aeff8c21061feb665affected · git
    • ed842faeb2bd49256f00485402f3113205f91d30 and later · before 7a894eb5de246d79f13105c55a67381039a24d44affected · git
    • ed842faeb2bd49256f00485402f3113205f91d30 and later · before a12cdaa3375f0bd3c8f4e564be7c143529abfe5baffected · git
    • ed842faeb2bd49256f00485402f3113205f91d30 and later · before aa73deb3b6b730ec280d45b3f423bfa9e17bc122affected · git
    • ed842faeb2bd49256f00485402f3113205f91d30 and later · before 33dec6f10777d5a8f71c0a200f690da5ae3c2e55affected · git
    • ed842faeb2bd49256f00485402f3113205f91d30 and later · before 20ef5c25422f97dd09d751e5ae6c18406cdc78e6affected · git
    • ed842faeb2bd49256f00485402f3113205f91d30 and later · before e5e890630533bdc15b26a34bb8e7ef539bdf1322affected · git
    • before 4.15not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.170-16.1.170-1
Debian:13linuxbefore 6.12.85-16.12.85-1
Debian:14linuxbefore 6.19.8-16.19.8-1
Red Hat:rhel_e4s:9.2::appstreamruncbefore 4:1.2.9-1.el9_2.24:1.2.9-1.el9_2.2
Red Hat:rhel_e4s:9.2::appstreamrunc-debuginfobefore 4:1.2.9-1.el9_2.24:1.2.9-1.el9_2.2
Red Hat:rhel_e4s:9.2::appstreamrunc-debugsourcebefore 4:1.2.9-1.el9_2.24:1.2.9-1.el9_2.2

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-2026-23378Mar 25, 2026 · net/sched: act_ife: Fix metalist update behavior
    31Monitor
  • ← EarlierCVE-2026-23379Mar 25, 2026 · net/sched: ets: fix divide by zero in the offload path
    22Monitor
  • Later →CVE-2026-23382Mar 25, 2026 · HID: Add HID_CLAIMED_INPUT guards in raw_event callbacks missing them
    22Monitor

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 Linux20ef5c25422f97dd09d751e5ae6c18406cdc78e6Vendor (CNA)
Linux Linux33dec6f10777d5a8f71c0a200f690da5ae3c2e55Vendor (CNA)
Linux Linux7a894eb5de246d79f13105c55a67381039a24d44Vendor (CNA)
Linux Linuxa12cdaa3375f0bd3c8f4e564be7c143529abfe5bVendor (CNA)
Linux Linuxa5c56e65b685360dd3f2278aeff8c21061feb665Vendor (CNA)
Linux Linuxa9d712ccfeef737c0e700a4b5b98f310e07b6b60Vendor (CNA)
Linux Linuxaa73deb3b6b730ec280d45b3f423bfa9e17bc122Vendor (CNA)
Linux Linuxe5e890630533bdc15b26a34bb8e7ef539bdf1322Vendor (CNA)
azl3 kernel 6.6.126.1-1 on Azure Linux 3.06.6.130.1-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
cbl2 kernel 5.15.202.1-1 on CBL-Mariner 2.0Release NotesMicrosoft (MSRC)
debian:linux6.1.170-1 · Debian:12Package registry (OSV)
red hat:runc4:1.2.9-1.el9_2.2 · Red Hat:rhel_e4s:9.2::appstreamPackage registry (OSV)
red hat:runc-debuginfo4:1.2.9-1.el9_2.2 · Red Hat:rhel_e4s:9.2::appstreamPackage registry (OSV)
red hat:runc-debugsource4:1.2.9-1.el9_2.2 · Red Hat:rhel_e4s:9.2::appstreamPackage registry (OSV)

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.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

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

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

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

Weakness class (CWE)

CWE-476 · NULL Pointer Dereference

CVSS vector

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

nvd-primary

Attack context

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

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. SSVC exploitation— → none
  2. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (11 more)

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

All records