Slab use-after-free read via concurrent SMB negotiation
Published Aug 15, 2026 · Updated Aug 15, 2026
Use-after-free in Linux kernel ksmbd allows remote attackers to trigger a slab memory read via concurrent SMB2 NEGOTIATE requests. The smb3_preauth_hash_rsp() send path checks conn->preauth_info without holding ksmbd_conn_lock(), allowing another negotiate worker to free the object between the null check and Preauth_HashValue dereference. Two requests must race on the same SMB connection, and the published record confirms the invalid read without documenting a demonstrated memory disclosure, code execution, or kernel crash.
Summary
What happened
Use-after-free in Linux kernel ksmbd allows remote attackers to trigger a slab memory read via concurrent SMB2 NEGOTIATE requests. The smb3_preauth_hash_rsp() send path checks conn->preauth_info without holding ksmbd_conn_lock(), allowing another negotiate worker to free the object between the null check and Preauth_HashValue dereference. Two requests must race on the same SMB connection, and the published record confirms the invalid read without documenting a demonstrated memory disclosure, code execution, or kernel crash.
The record
- CVE
- CVE-2026-72422
- Published
- Aug 15, 2026
- Updated
- Aug 15, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- Unavailable
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 15, 2026CVE publishedPublication date reported by the CVE source.
- Aug 15, 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.
- Affected versionversion=5.15.61 <5.15.212
- Affected versionversion=5.18.18 <5.19
- Affected versionversion=5.19.2 <5.20
- Affected versionversion=6.0
- Affected versionversion=8a8315a5960bd2b5ffc75f44fc089e57c3b17c44
- Affected versionversion=aa7253c2393f6dcd6a1468b0792f6da76edad917 <0c054227479ed7e36ebccb3a558bc0ef698264f6
- Affected versionversion=aa7253c2393f6dcd6a1468b0792f6da76edad917 <16a1ecf39c217e3d164bd32ef2a4f650abc067fa
- Affected versionversion=aa7253c2393f6dcd6a1468b0792f6da76edad917 <1c89da3baa2b1f269178afa87dc30479b8535776
- Affected versionversion=aa7253c2393f6dcd6a1468b0792f6da76edad917 <7470511d085af1c7a043a60e53d52b512d5a10b1
- Affected versionversion=aa7253c2393f6dcd6a1468b0792f6da76edad917 <77bb0bbfcc4e777ca653174689e5e363f8ee63d1
- Affected versionversion=aa7253c2393f6dcd6a1468b0792f6da76edad917 <d0a469122e7bf8338fec1949fb1e8e1290ed8caa
- Affected versionversion=dd4e4c811898410e6a3ae3b63207b7c542860907 <c7bef84740d1d57848c74f6f5b996606e43ea4fe
- Affected versionversion=ff20f1875889dbe4a67c9298e609d7c88cf6456d
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Weakness, pattern, technique
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Public exploit references
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Technologies
Your stack
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Your stack
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