CVE-2026-72310Network attack vector

Kernel memory disclosure via wrapped SMB response bounds

Published Aug 15, 2026 · Updated Aug 15, 2026

Out-of-bounds read in the Linux kernel SMB client allows remote attackers controlling an SMB server to disclose kernel memory. The smb2_ioctl_query_info() bounds check adds two untrusted 32-bit response fields directly, allowing OutputOffset plus the requested length to wrap before comparison. Reachability requires the client to process a crafted passthrough FSCTL response from a malicious SMB server; copy_to_user() then exposes data beyond the response buffer to userspace.

CVSS severity8.1
High
EPSS probability0.64%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds read in the Linux kernel SMB client allows remote attackers controlling an SMB server to disclose kernel memory. The smb2_ioctl_query_info() bounds check adds two untrusted 32-bit response fields directly, allowing OutputOffset plus the requested length to wrap before comparison. Reachability requires the client to process a crafted passthrough FSCTL response from a malicious SMB server; copy_to_user() then exposes data beyond the response buffer to userspace.

The record

CVE
CVE-2026-72310
Published
Aug 15, 2026
Updated
Aug 15, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-125, T1005
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 15, 2026CVE publishedPublication date reported by the CVE source.
  2. 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.

  1. Affected versionversion=2005c32ec99ee2490e8131b3953f3f212009ffea
  2. Affected versionversion=2b1116bbe898aefdf584838448c6869f69851e0f <160045fc943f6c46b227644261252c8a22b8a87a
  3. Affected versionversion=2b1116bbe898aefdf584838448c6869f69851e0f <1627e7d5c9b09721a141d07cedb178882f1ded67
  4. Affected versionversion=2b1116bbe898aefdf584838448c6869f69851e0f <175357ee0c596cb82054650dfa32fda51ad35aaa
  5. Affected versionversion=2b1116bbe898aefdf584838448c6869f69851e0f <1a638c55f2db6cb2296e5e3138015dd8fd9d4aa9
  6. Affected versionversion=2b1116bbe898aefdf584838448c6869f69851e0f <63feb687e89a3a52a31e6e01764117cc500f1974
  7. Affected versionversion=2b1116bbe898aefdf584838448c6869f69851e0f <a4f27ad055392fa164f5649e89a3637b033c5fcc
  8. Affected versionversion=2b1116bbe898aefdf584838448c6869f69851e0f <b30771b69eafae750afb7385fbcc3d77ed3f3670
  9. Affected versionversion=2b1116bbe898aefdf584838448c6869f69851e0f <dbd126539c098dba3159ce7d34b10b2daddcbd0f
  10. Affected versionversion=5.4.69 <5.5
  11. Affected versionversion=5.5

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=2005c32ec99ee2490e8131b3953f3f212009ffea; version=2b1116bbe898aefdf584838448c6869f69851e0f <160045fc943f6c46b227644261252c8a22b8a87a; version=2b1116bbe898aefdf584838448c6869f69851e0f <1627e7d5c9b09721a141d07cedb178882f1ded67; version=2b1116bbe898aefdf584838448c6869f69851e0f <175357ee0c596cb82054650dfa32fda51ad35aaa; version=2b1116bbe898aefdf584838448c6869f69851e0f <1a638c55f2db6cb2296e5e3138015dd8fd9d4aa9; version=2b1116bbe898aefdf584838448c6869f69851e0f <63feb687e89a3a52a31e6e01764117cc500f1974; version=2b1116bbe898aefdf584838448c6869f69851e0f <a4f27ad055392fa164f5649e89a3637b033c5fcc; version=2b1116bbe898aefdf584838448c6869f69851e0f <b30771b69eafae750afb7385fbcc3d77ed3f3670; version=2b1116bbe898aefdf584838448c6869f69851e0f <dbd126539c098dba3159ce7d34b10b2daddcbd0f; version=5.4.69 <5.5; version=5.5

Published CVSS scores

7.0Red HatCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
8.1CanonicalCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-125Out-of-bounds Read
T1005Data from Local System

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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