CVE-2026-45972Network attack vector

Memory corruption via stale SMB retry state

Published May 27, 2026 · Updated May 27, 2026

Use-after-free and double-free flaws in the Linux kernel SMB client allow remote attackers to corrupt kernel memory through SMB2 responses. In smb2_open_file(), an access-denied retry frees the first SMB2_open() error buffer but retains err_iov and err_buftype, so later cleanup reuses the stale pointer or frees it again. The path requires an SMB open retry without FILE_READ_ATTRIBUTES; non-null data triggers the use-after-free path, while null data triggers the double free and can crash the kernel.

CVSS severity9.8
Critical
EPSS probability0.33%
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 and double-free flaws in the Linux kernel SMB client allow remote attackers to corrupt kernel memory through SMB2 responses. In smb2_open_file(), an access-denied retry frees the first SMB2_open() error buffer but retains err_iov and err_buftype, so later cleanup reuses the stale pointer or frees it again. The path requires an SMB open retry without FILE_READ_ATTRIBUTES; non-null data triggers the use-after-free path, while null data triggers the double free and can crash the kernel.

The record

CVE
CVE-2026-45972
Published
May 27, 2026
Updated
May 27, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-416, CWE-825, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 27, 2026CVE publishedPublication date reported by the CVE source.
  2. May 27, 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=3a6d6b332f92990958602c1e35ce0173e2dd62e9 <7425453ea16dbc3bbb0f6cac4d60b537e5e4d151
  2. Affected versionversion=6.1.163 <6.1.165
  3. Affected versionversion=6.12.70 <6.12.75
  4. Affected versionversion=6.18.10 <6.18.14
  5. Affected versionversion=6.19
  6. Affected versionversion=6.6.124 <6.6.128
  7. Affected versionversion=743f70406264348c0830f38409eb6c40a42fb2db <96e53bb3ee2f354cf6b4ab07bcc56e500f8b3f74
  8. Affected versionversion=9ee608a64e37cea5b4b13e436c559dd0fb2ad1b5 <e66dcf7bb9c4df5582c82bc3582725abcbfbea73
  9. Affected versionversion=b64e3b5d8d759dd4333992e4ba4dadf9359952c8 <4d339b219004869e96c4ce56b8891f83a38da4c0
  10. Affected versionversion=e3a43633023e3cacaca60d4b8972d084a2b06236 <639deb962986ef2f5e2a6d5a600c66f922471e81
  11. Affected versionversion=e3a43633023e3cacaca60d4b8972d084a2b06236 <ebbbc4bfad4cb355d17c671223d0814ee3ef4eda

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=3a6d6b332f92990958602c1e35ce0173e2dd62e9 <7425453ea16dbc3bbb0f6cac4d60b537e5e4d151; version=6.1.163 <6.1.165; version=6.12.70 <6.12.75; version=6.18.10 <6.18.14; version=6.19; version=6.6.124 <6.6.128; version=743f70406264348c0830f38409eb6c40a42fb2db <96e53bb3ee2f354cf6b4ab07bcc56e500f8b3f74; version=9ee608a64e37cea5b4b13e436c559dd0fb2ad1b5 <e66dcf7bb9c4df5582c82bc3582725abcbfbea73; version=b64e3b5d8d759dd4333992e4ba4dadf9359952c8 <4d339b219004869e96c4ce56b8891f83a38da4c0; version=e3a43633023e3cacaca60d4b8972d084a2b06236 <639deb962986ef2f5e2a6d5a600c66f922471e81; version=e3a43633023e3cacaca60d4b8972d084a2b06236 <ebbbc4bfad4cb355d17c671223d0814ee3ef4eda

Published CVSS scores

9.8Linux CNACVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.7UbuntuCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
7.0UbuntuCVSS:3.1/AV:L/AC:H/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

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

Weakness, pattern, technique

CWE-416Use After Free
CWE-825Expired Pointer Dereference
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

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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