CVE-2024-26828Network attack vector

Kernel-memory disclosure and crash via CIFS underflow

Published Apr 17, 2024 · Updated Aug 5, 2026

Out-of-bounds access in the Linux CIFS client allows remote attackers to disclose kernel memory or crash the host via a crafted SMB reply. In fs/smb/client/smb2ops.c, parse_server_interfaces() compares signed bytes_left with unsigned sizeof(), so a negative remainder becomes a large value and the loop walks beyond the reply buffer. A malicious or compromised SMB server can trigger the flaw after a client mounts its share; exposed data can enter /proc/fs/cifs/DebugData, while an invalid pointer walk can oops the kernel.

CVSS severity9.4
Critical
EPSS probability0.75%
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 access in the Linux CIFS client allows remote attackers to disclose kernel memory or crash the host via a crafted SMB reply. In fs/smb/client/smb2ops.c, parse_server_interfaces() compares signed bytes_left with unsigned sizeof(), so a negative remainder becomes a large value and the loop walks beyond the reply buffer. A malicious or compromised SMB server can trigger the flaw after a client mounts its share; exposed data can enter /proc/fs/cifs/DebugData, while an invalid pointer walk can oops the kernel.

The record

CVE
CVE-2024-26828
Published
Apr 17, 2024
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-191, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 17, 2024CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 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=4.18
  2. Affected versionversion=fe856be475f7cf5ffcde57341d175ce9fd09434b <7190353835b4a219abb70f90b06cdcae97f11512
  3. Affected versionversion=fe856be475f7cf5ffcde57341d175ce9fd09434b <cffe487026be13eaf37ea28b783d9638ab147204
  4. Affected versionversion=fe856be475f7cf5ffcde57341d175ce9fd09434b <df2af9fdbc4ddde18a3371c4ca1a86596e8be301
  5. Affected versionversion=fe856be475f7cf5ffcde57341d175ce9fd09434b <f7ff1c89fb6e9610d2b01c1821727729e6609308

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=4.18; version=fe856be475f7cf5ffcde57341d175ce9fd09434b <7190353835b4a219abb70f90b06cdcae97f11512; version=fe856be475f7cf5ffcde57341d175ce9fd09434b <cffe487026be13eaf37ea28b783d9638ab147204; version=fe856be475f7cf5ffcde57341d175ce9fd09434b <df2af9fdbc4ddde18a3371c4ca1a86596e8be301; version=fe856be475f7cf5ffcde57341d175ce9fd09434b <f7ff1c89fb6e9610d2b01c1821727729e6609308

Published CVSS scores

9.4Linux CNACVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:H
6.7CISA-ADPCVSS:3.1/AV:A/AC:L/PR:L/UI:R/S:U/C:N/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

CWE-191Integer Underflow (Wrap or Wraparound)
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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