CVE-2022-50859Network attack vector

Two-byte memory disclosure via oversized negotiation request

Published Dec 30, 2025 · Updated Dec 30, 2025

Information disclosure in Linux kernel CIFS allows remote attackers operating SMB servers to read uninitialized kernel memory. The smb3_validate_negotiate function subtracts space for only two unused dialect entries after the request structure grew to four, so it sends a 28-byte VALIDATE_NEGOTIATE_INFO body instead of 26 bytes. Exploitation requires a CIFS client to validate negotiation with an attacker-controlled SMB server, which receives two unintended bytes from the uninitialized message body.

CVSS severityUnavailable
Unscored
EPSS probability0.24%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Information disclosure in Linux kernel CIFS allows remote attackers operating SMB servers to read uninitialized kernel memory. The smb3_validate_negotiate function subtracts space for only two unused dialect entries after the request structure grew to four, so it sends a 28-byte VALIDATE_NEGOTIATE_INFO body instead of 26 bytes. Exploitation requires a CIFS client to validate negotiation with an attacker-controlled SMB server, which receives two unintended bytes from the uninitialized message body.

The record

CVE
CVE-2022-50859
Published
Dec 30, 2025
Updated
Dec 30, 2025
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
network
Privileges
Unavailable

Timeline

How it unfolded

  1. Dec 30, 2025CVE publishedPublication date reported by the CVE source.
  2. Dec 30, 2025Record 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=5.0
  2. Affected versionversion=d5c7076b772ad7dcdb92303397b36aee8fa0d25d <60480291c1fcafad8425d93f771b5bcc2bd398b4
  3. Affected versionversion=d5c7076b772ad7dcdb92303397b36aee8fa0d25d <9312e04b6c6bc46354ecd0cc82052a2b3df0b529
  4. Affected versionversion=d5c7076b772ad7dcdb92303397b36aee8fa0d25d <943eb0ede74ecd609fdfd3f0b83e0d237613e526
  5. Affected versionversion=d5c7076b772ad7dcdb92303397b36aee8fa0d25d <d0050ec3ebbcb3451df9a65b8460be9b9e02e80c
  6. Affected versionversion=d5c7076b772ad7dcdb92303397b36aee8fa0d25d <e98ecc6e94f4e6d21c06660b0f336df02836694f
  7. Affected versionversion=d5c7076b772ad7dcdb92303397b36aee8fa0d25d <fada9b8c95c77bb46b89e18117405bc90fce9f74

What conditions does exploitation require?

Attack vectornetwork
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=5.0; version=d5c7076b772ad7dcdb92303397b36aee8fa0d25d <60480291c1fcafad8425d93f771b5bcc2bd398b4; version=d5c7076b772ad7dcdb92303397b36aee8fa0d25d <9312e04b6c6bc46354ecd0cc82052a2b3df0b529; version=d5c7076b772ad7dcdb92303397b36aee8fa0d25d <943eb0ede74ecd609fdfd3f0b83e0d237613e526; version=d5c7076b772ad7dcdb92303397b36aee8fa0d25d <d0050ec3ebbcb3451df9a65b8460be9b9e02e80c; version=d5c7076b772ad7dcdb92303397b36aee8fa0d25d <e98ecc6e94f4e6d21c06660b0f336df02836694f; version=d5c7076b772ad7dcdb92303397b36aee8fa0d25d <fada9b8c95c77bb46b89e18117405bc90fce9f74

Published CVSS scores

No CVSS assessment is available in this record.

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
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

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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