CVE-2026-31536Network attack vector

Memory corruption via unsignaled send completion

Published Apr 24, 2026 · Updated Apr 24, 2026

Use-after-free in the SMB Direct server in Linux Kernel 5.15 through 6.18.10 and 6.19 allows remote attackers to corrupt kernel memory. On an errored unsignaled batch completion, send_done frees the shared send_io and its sibling requests before ib_drain_qp completes those siblings. Reachability requires the ksmbd SMB Direct RDMA transport and a broken connection that completes requests lacking IB_SEND_SIGNALED.

CVSS severity9.8
Critical
EPSS probability0.44%
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 SMB Direct server in Linux Kernel 5.15 through 6.18.10 and 6.19 allows remote attackers to corrupt kernel memory. On an errored unsignaled batch completion, send_done frees the shared send_io and its sibling requests before ib_drain_qp completes those siblings. Reachability requires the ksmbd SMB Direct RDMA transport and a broken connection that completes requests lacking IB_SEND_SIGNALED.

The record

CVE
CVE-2026-31536
Published
Apr 24, 2026
Updated
Apr 24, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 24, 2026CVE publishedPublication date reported by the CVE source.
  2. 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.

  1. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <24082642654f3e5149913946e89c00a297a8868f
  2. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <9da82dc73cb03e85d716a2609364572367a5ff47
  3. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <e38b415c024bc3b6321bf8650dbf3f4aab8e74b3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <24082642654f3e5149913946e89c00a297a8868f; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <9da82dc73cb03e85d716a2609364572367a5ff47; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <e38b415c024bc3b6321bf8650dbf3f4aab8e74b3

Published CVSS scores

9.8kernel.orgCVSS:3.1/AV:N/AC:L/PR:N/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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

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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