CVE-2026-99083Network attack vector

Kernel heap corruption via compound-response size miscalculation

Published Oct 23, 2026 · Updated Oct 23, 2026

Heap corruption in Linux ksmbd allows remote attackers to overwrite kernel memory via compounded SMB2 Kerberos session setup requests. In krb5_authenticate(), the response-space calculation omits work->next_smb2_rsp_hdr_off, allowing the AP-REP copy to exceed response_buf when session setup follows earlier compound elements. Exposure requires a running ksmbd server using Kerberos; the public record does not establish code execution or a specific crash outcome.

CVSS severityUnavailable
Unscored
EPSS probability0.45%
Next 30 days · Nov 1, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap corruption in Linux ksmbd allows remote attackers to overwrite kernel memory via compounded SMB2 Kerberos session setup requests. In krb5_authenticate(), the response-space calculation omits work->next_smb2_rsp_hdr_off, allowing the AP-REP copy to exceed response_buf when session setup follows earlier compound elements. Exposure requires a running ksmbd server using Kerberos; the public record does not establish code execution or a specific crash outcome.

The record

CVE
CVE-2026-99083
Published
Oct 23, 2026
Updated
Oct 23, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
network
Privileges
Unavailable

Timeline

How it unfolded

  1. Oct 23, 2026CVE publishedPublication date reported by the CVE source.
  2. Oct 23, 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=0 <6.12.114
  2. Affected versionversion=0 <6.18.58
  3. Affected versionversion=0 <6.6.160
  4. Affected versionversion=0 <7.2.12
  5. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <23a0be6a84a38ac169eeab49017934e8e27c65f0
  6. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <4722d06b2907585074252061b1024a696c1cfc23
  7. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <517404e157395d0f8da125ca956c566895dfcd06
  8. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <59c6dcc5dd9dafe764ca0d40525933b2be69b059
  9. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <80af1bde97d5a85ad6f2c40ca894ccc8fa75a27a

What conditions does exploitation require?

Attack vectornetwork
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=0 <6.12.114; version=0 <6.18.58; version=0 <6.6.160; version=0 <7.2.12; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <23a0be6a84a38ac169eeab49017934e8e27c65f0; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <4722d06b2907585074252061b1024a696c1cfc23; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <517404e157395d0f8da125ca956c566895dfcd06; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <59c6dcc5dd9dafe764ca0d40525933b2be69b059; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <80af1bde97d5a85ad6f2c40ca894ccc8fa75a27a

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.

Activity data is delayed. The latest report is Sep 28, 2026.

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

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 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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