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CVE Record

CVE-2026-23001: macvlan: fix possible UAF in macvlan_forward_source()

In the Linux kernel, the following vulnerability has been resolved: macvlan: fix possible UAF in macvlan_forward_source() Add RCU protection on (struct macvlan_source_entry)->vlan. Whenever macvlan_hash_del_source() is called, we must clear entry->vlan pointer before RCU grace period starts. This allows macvlan_forward_source() to skip over entries queued for freeing. Note that macvlan_dev are already RCU protected, as they are embedded in a standard netdev (netdev_priv(ndev)). https: //lore.kernel.org/netdev/695fb1e8.050a0220.1c677c.039f.GAE@google.com/T/#u

HighCVSS 7.8Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

CVE-2026-23001 is a Linux kernel memory safety flaw in macvlan networking. A local authenticated user could potentially trigger use-after-free behavior that may impact confidentiality, integrity, or availability. The business risk is highest on Linux hosts where untrusted users, containers, or workloads can interact with macvlan-related networking paths.

Executive priority

Treat as a high-priority kernel update for shared Linux infrastructure. It requires local privileges, so internet-facing urgency is lower than remote bugs, but impact can be severe on multi-user or containerized systems.

Technical view

The issue is a possible use-after-free in macvlan_forward_source(). The fix adds RCU protection for macvlan_source_entry->vlan and clears the pointer before the RCU grace period starts, allowing forwarding logic to skip entries queued for freeing.

Likely exposure

Exposure is likely limited to Linux systems running affected kernel versions with macvlan functionality present, especially multi-tenant hosts, container platforms, and systems where local users or workloads can exercise networking behavior.

Exploitation context

The CVSS vector is local, low complexity, privileges required, and no user interaction. The source bundle does not show CISA KEV listing or cited evidence of active exploitation.

Researcher notes

The public description is focused on the kernel fix, not exploitability details. Validation should center on kernel lineage, vendor backports, and macvlan usage. Do not assume remote reachability or active exploitation from the provided evidence.

Mitigation direction

  • Apply vendor kernel updates containing the referenced stable fixes.
  • Prioritize multi-tenant Linux hosts and container infrastructure using macvlan.
  • Check distribution advisories for backported fixes and package-specific status.
  • Review whether macvlan is required on exposed or shared systems.

Validation and detection

  • Inventory Linux kernel versions across servers and container hosts.
  • Compare deployed kernels against vendor advisories and referenced stable commits.
  • Identify hosts using macvlan networking or related container network configurations.
  • Confirm updated kernels are booted after patching, not merely installed.
Prepared
Confidence
medium
Sources
9

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

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CVE-2026-23001 mapping review

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Vulnerability profileCVE Program record
Severity
High
CVSS
7.8 (3.1)
Known Exploited
No
Published

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

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
3Timeline events
0ADP providers
8Source links

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
7.8CVSS 3.1HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H1.85.9Linux

Vulnerability scoring details

Base CVSS 3.1 score

7.8High
CVSS 3.1 vector shape for CVE-2026-23001Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux79cf79abce71eb7dbc40e2f3121048ca5405cb47, 79cf79abce71eb7dbc40e2f3121048ca5405cb47, 79cf79abce71eb7dbc40e2f3121048ca5405cb47, 79cf79abce71eb7dbc40e2f3121048ca5405cb47, 79cf79abce71eb7dbc40e2f3121048ca5405cb47, 79cf79abce71eb7dbc40e2f3121048ca5405cb47, 79cf79abce71eb7dbc40e2f3121048ca5405cb47unaffected
LinuxLinux3.18, 0, 5.10.249, 5.15.199, 6.1.162, 6.6.122, 6.12.67, 6.18.7, 6.19affected
Weakness

CWE details

No CWE listed

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