Service interruption via receive-credit accounting race
Published Apr 24, 2026 · Updated Apr 24, 2026
Race condition in SMB Direct in Linux Kernel 6.18 through 6.18.10 and 6.19 allows remote attackers to cause an SMB service interrupt. The receive-credit path subtracts granted credits from posted receive buffers even after a peer has consumed a credit, so completion processing can grant nonexistent credits. The network path requires an SMB Direct RDMA connection; the published assessment reports only availability impact, not data disclosure or modification.
Summary
What happened
Race condition in SMB Direct in Linux Kernel 6.18 through 6.18.10 and 6.19 allows remote attackers to cause an SMB service interrupt. The receive-credit path subtracts granted credits from posted receive buffers even after a peer has consumed a credit, so completion processing can grant nonexistent credits. The network path requires an SMB Direct RDMA connection; the published assessment reports only availability impact, not data disclosure or modification.
The record
- CVE
- CVE-2026-31539
- Published
- Apr 24, 2026
- Updated
- Apr 24, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux Kernel
- Classifications
- T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
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=5fb9b459b3686e366640edd4e62805ef7b4de927 <6e3c5052f9686192e178806e017b7377155f4bab
- Affected versionversion=5fb9b459b3686e366640edd4e62805ef7b4de927 <e811e60e1cc79923c4388146eb1fa26a7482731e
- Affected versionversion=5fb9b459b3686e366640edd4e62805ef7b4de927 <f99996870222b598914a1f49d7375dc23752c237
- Affected versionversion=6.18
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
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
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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