CVE-2026-23273Public exploit

Kernel compromise via missing RCU grace period

Published Mar 20, 2026 · Updated Mar 20, 2026

Use-after-free in the Linux kernel macvlan driver allows local users to compromise kernel confidentiality, integrity, and availability. macvlan_common_newlink() can publish a device before detecting an error, after which rtnl_newlink() frees it without waiting for an RCU grace period while macvlan_forward_source() still reads it. Triggering requires low-privilege local access and a race between failed macvlan creation and packet forwarding; successful triggering can crash the kernel or corrupt kernel memory.

CVSS severity7.8
High
EPSS probability0.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in the Linux kernel macvlan driver allows local users to compromise kernel confidentiality, integrity, and availability. macvlan_common_newlink() can publish a device before detecting an error, after which rtnl_newlink() frees it without waiting for an RCU grace period while macvlan_forward_source() still reads it. Triggering requires low-privilege local access and a race between failed macvlan creation and packet forwarding; successful triggering can crash the kernel or corrupt kernel memory.

The record

CVE
CVE-2026-23273
Published
Mar 20, 2026
Updated
Mar 20, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-416, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 20, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 20, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=11ba9f0dc865136174cb98834280fb21bbc950c7 <19c7d8ac51988d053709c1e85bd8482076af845d
  2. Affected versionversion=5dae6b36a7cb7a4fcf4121b95e9ca7f96f816c8a <3d94323c80d7fc4da5f10f9bb06a45d39d5d3cc4
  3. Affected versionversion=6.19
  4. Affected versionversion=986967a162142710076782d5b93daab93a892980 <a1f686d273d129b45712d95f4095843b864466bd
  5. Affected versionversion=c43d0e787cbba569ec9d11579ed370b50fab6c9c <721eb342d9ba19bad5c4815ea3921465158b7362
  6. Affected versionversion=cdedcd5aa3f3cb8b7ae0f87ab3a936d0bd583d66 <d34f7a8aa9a25b7e64e0e46e444697c0f702374d
  7. Affected versionversion=da5c6b8ae47e414be47e5e04def15b25d5c962dc <91e4ff8d966978901630fc29582c1a76d3c6e46c
  8. Affected versionversion=f8db6475a83649689c087a8f52486fcc53e627e9 <1e58ae87ad1e6e24368dea9aec9048c758cd0e2b
  9. Affected versionversion=f8db6475a83649689c087a8f52486fcc53e627e9 <e3f000f0dee1bfab52e2e61ca6a3835d9e187e35

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=11ba9f0dc865136174cb98834280fb21bbc950c7 <19c7d8ac51988d053709c1e85bd8482076af845d; version=5dae6b36a7cb7a4fcf4121b95e9ca7f96f816c8a <3d94323c80d7fc4da5f10f9bb06a45d39d5d3cc4; version=6.19; version=986967a162142710076782d5b93daab93a892980 <a1f686d273d129b45712d95f4095843b864466bd; version=c43d0e787cbba569ec9d11579ed370b50fab6c9c <721eb342d9ba19bad5c4815ea3921465158b7362; version=cdedcd5aa3f3cb8b7ae0f87ab3a936d0bd583d66 <d34f7a8aa9a25b7e64e0e46e444697c0f702374d; version=da5c6b8ae47e414be47e5e04def15b25d5c962dc <91e4ff8d966978901630fc29582c1a76d3c6e46c; version=f8db6475a83649689c087a8f52486fcc53e627e9 <1e58ae87ad1e6e24368dea9aec9048c758cd0e2b; version=f8db6475a83649689c087a8f52486fcc53e627e9 <e3f000f0dee1bfab52e2e61ca6a3835d9e187e35

Published CVSS scores

7.8kernel.orgCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-416Use After Free
T1068Exploitation for Privilege Escalation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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