Service interruption via unsynchronized SMB Direct credits
Published Apr 24, 2026 · Updated Apr 24, 2026
A send-credit synchronization flaw in Linux Kernel 5.15 through 6.18.10 and 6.19 allows local users to interrupt ksmbd SMB Direct service. The ksmbd RDMA send path does not hold one batch credit across all fragments, so an immediate empty send can interleave and corrupt the reassembled data stream. Exploitation requires a kernel with ksmbd SMB Direct support and low-privilege local access; the reported consequence is availability loss without data disclosure or modification.
Summary
What happened
A send-credit synchronization flaw in Linux Kernel 5.15 through 6.18.10 and 6.19 allows local users to interrupt ksmbd SMB Direct service. The ksmbd RDMA send path does not hold one batch credit across all fragments, so an immediate empty send can interleave and corrupt the reassembled data stream. Exploitation requires a kernel with ksmbd SMB Direct support and low-privilege local access; the reported consequence is availability loss without data disclosure or modification.
The record
- CVE
- CVE-2026-31537
- Published
- Apr 24, 2026
- Updated
- Apr 24, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux Kernel
- Classifications
- CWE-821, T1499
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Apr 24, 2026CVE publishedPublication date reported by the CVE source.
- Apr 24, 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=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <34abd408c8ba24d7c97bd02ba874d8c714f49db1
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <5ef18a2e66f2f33fdac64437bddfb9fe6389fdc7
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <79242e7b6bc63efec28b7c235bc320806afce6c0
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
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Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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