CVE-2026-64381

Denial of service via compound PDU buffer leak

Published Jul 25, 2026 · Updated Jul 25, 2026

Memory leak in the Linux kernel SMB client allows local users to exhaust kernel memory through crafted encrypted compound PDUs. receive_encrypted_standard() allocates next_buffer before checking MAX_COMPOUND, then returns without attaching or freeing it when the limit is reached. Exploitation requires low-privileged access to connect the SMB client to an attacker-controlled server that repeatedly sends over-limit compounds, causing service interruption.

CVSS severity5.5
Medium
EPSS probability0.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory leak in the Linux kernel SMB client allows local users to exhaust kernel memory through crafted encrypted compound PDUs. receive_encrypted_standard() allocates next_buffer before checking MAX_COMPOUND, then returns without attaching or freeing it when the limit is reached. Exploitation requires low-privileged access to connect the SMB client to an attacker-controlled server that repeatedly sends over-limit compounds, causing service interruption.

The record

CVE
CVE-2026-64381
Published
Jul 25, 2026
Updated
Jul 25, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-772, T1499.001
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 25, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 25, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=4.19
  2. Affected versionversion=b24df3e30cbf48255db866720fb71f14bf9d2f39 <07e0ab81df1790afa35732a4e8e07ff831b29008
  3. Affected versionversion=b24df3e30cbf48255db866720fb71f14bf9d2f39 <1c6267a1d5cf4c73b656f8181b310cbbb3e4767b
  4. Affected versionversion=b24df3e30cbf48255db866720fb71f14bf9d2f39 <297243e365fc9fe2f8e9b7dd535a65d922cd108b
  5. Affected versionversion=b24df3e30cbf48255db866720fb71f14bf9d2f39 <67097772df7791c53d608f04bd31c676ccf79b83
  6. Affected versionversion=b24df3e30cbf48255db866720fb71f14bf9d2f39 <68fc0b6cc03ca58060c0f36454e169f5fe258974
  7. Affected versionversion=b24df3e30cbf48255db866720fb71f14bf9d2f39 <9136a08dc29328edd9867f2545e73906ac9df93b
  8. Affected versionversion=b24df3e30cbf48255db866720fb71f14bf9d2f39 <927d4805aea0a287d36dd4f826ee24d69a2afee3
  9. Affected versionversion=b24df3e30cbf48255db866720fb71f14bf9d2f39 <94e4f672db029414b9888b5137a7559f1febf2d8

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=4.19; version=b24df3e30cbf48255db866720fb71f14bf9d2f39 <07e0ab81df1790afa35732a4e8e07ff831b29008; version=b24df3e30cbf48255db866720fb71f14bf9d2f39 <1c6267a1d5cf4c73b656f8181b310cbbb3e4767b; version=b24df3e30cbf48255db866720fb71f14bf9d2f39 <297243e365fc9fe2f8e9b7dd535a65d922cd108b; version=b24df3e30cbf48255db866720fb71f14bf9d2f39 <67097772df7791c53d608f04bd31c676ccf79b83; version=b24df3e30cbf48255db866720fb71f14bf9d2f39 <68fc0b6cc03ca58060c0f36454e169f5fe258974; version=b24df3e30cbf48255db866720fb71f14bf9d2f39 <9136a08dc29328edd9867f2545e73906ac9df93b; version=b24df3e30cbf48255db866720fb71f14bf9d2f39 <927d4805aea0a287d36dd4f826ee24d69a2afee3; version=b24df3e30cbf48255db866720fb71f14bf9d2f39 <94e4f672db029414b9888b5137a7559f1febf2d8

Published CVSS scores

5.5Red HatCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-772Missing Release of Resource after Effective Lifetime
T1499.001OS Exhaustion Flood

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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