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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

A Linux kernel macvlan networking flaw can access memory after it has been freed. A local, low-privileged attacker may be able to crash the host or compromise confidentiality and integrity. Exposure depends on the affected macvlan code path being reachable; the supplied evidence does not fully define operational prerequisites.

Executive priority

Treat as a high-priority kernel update for exposed shared Linux infrastructure, especially container or virtualization hosts using macvlan. Schedule prompt remediation through normal emergency patch governance; broader urgency should reflect confirmed macvlan use and local-user access.

Technical view

macvlan_forward_source() may dereference a macvlan_source_entry vlan pointer queued for freeing. The fix adds RCU protection and clears the pointer before the RCU grace period, allowing forwarding to skip entries being removed. CVSS 3.1 is 7.8: local access, low complexity, low privileges, no user interaction, and potentially high confidentiality, integrity, and availability impact.

Likely exposure

Potentially affected Linux kernels include the versions identified in the CVE record. Practical exposure is most likely on systems using macvlan networking and exercising source forwarding, but the source bundle does not establish exact configuration requirements or distribution-specific package status.

Exploitation context

The CVSS vector describes local, low-privileged exploitation without user interaction. The supplied record is not in KEV and provides no evidence of active exploitation or a public exploit. It also does not establish whether exploitation reliably produces code execution rather than a crash or other memory corruption.

Researcher notes

The defect is a race-sensitive use-after-free involving RCU lifetime handling. The record names multiple stable commits but does not map each commit to a specific distribution package. Repeated commit hashes and ambiguous version entries in the affected data reduce precision; validate against vendor advisories and kernel ancestry.

Mitigation direction

  • Apply the applicable vendor kernel update containing the macvlan RCU fix.
  • Prioritize multi-user, container, and virtualization hosts using macvlan networking.
  • Consult distribution advisories for fixed package versions and reboot requirements.
  • Where updating is delayed, assess whether macvlan use can be safely reduced.

Validation and detection

  • Inventory running kernel versions across Linux hosts.
  • Identify hosts, containers, or workloads configured with macvlan networking.
  • Confirm vendor kernels include the applicable referenced stable commit.
  • Verify hosts booted into the updated kernel after maintenance.
  • Regression-test macvlan connectivity and source forwarding after updating.
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

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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
1ADP providers
8Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: total

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.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc

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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