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Vulnerabilities/CVE-2026-46243Public Intelligence Dossier
Source: linux · Limited verification•Last verified: •Collection Running
CVE-2026-46243Unknown / EvaluatingHIGH (raw)CVSS 7.8NVD-CWE-noinfo

In the Linux kernel, the following vulnerability has been resolved: smb: client: reject userspace cifs.spnego descriptions cifs.spnego key descriptions contain authority-bearing fields such as pid, uid, creduid, and upcall_target that cifs.upcall treats as kernel-originating inputs

Published: 01 Jun 2026•Last updated: 15 Oct 2026, 07:49 AM IST•Source identifier: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Dossier completeness: source-provided sections 2 / 3 · rule guidance available. Missing source facts count as incomplete.
Official source
CISA KEV catalog
Unknown
KEV status was not determined.
CVSS score
7.8HIGH (raw)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Metric source134c704f-9b21-4f2e-91b3-4a467353bcc0
EPSS probability
0.4%0.004
Percentile30th
Weakness type
NVD-CWE-noinfo
CWE-20, CWE-825
Remediation
Patch status unknown
No fixed version or KB recorded

Why It Matters

Analysis dossier

Why It Matters

In the Linux kernel, the following vulnerability has been resolved: smb: client: reject userspace cifs.spnego descriptions cifs.spnego key descriptions contain authority-bearing fields such as pid, uid, creduid, and upcall_target that cifs.upcall treats as kernel-originating inputs. However, userspace can also create keys of this type through request_key(2) or add_key(2), allowing those fields to be supplied without CIFS origin. Only accept cifs.spnego descriptions while CIFS is using its private spnego_cred to request the key.

SOC priority

High

Actively exploited

Unknown

Publicly disclosed

Unknown

Risk basis: SOC ecosystem technology relevance; HIGH severity; No confirmed exploitation signal in current enrichment

Affected Products & Remediation

1 source-backed product
Affected products and versions (source)
  • linux linux kernel · >= 2.6.24.1 < 5.10.258; >= 5.11 < 5.15.209; >= 5.16 < 6.1.175; >= 6.2 < 6.6.142; >= 6.7 < 6.12.92; >= 6.13 < 6.18.34; >= 6.19 < 7.0.11; 2.6.24; 7.1 · NVD CPE · Source
Recorded patch / KBNot provided by source

Vendor or catalog guidance (source)

Not provided by source

Known exploitation (source facts)

Only what a source states. Unknown means no source has said either way; it is not "not exploited".

CISA KEV
Unknown
Exploited (source statement)
Unknown
Publicly disclosed (source)
Unknown

Suggested hunting (rule-based inference)

SecOps Signal recommendation (rule-based inference). These steps are hunting hypotheses from the vulnerability class; they do not state or imply that exploitation occurred here or anywhere.

Matched local-privilege-escalation (CVSS AV:L, CVSS PR:L)

Exposure

  1. Identify hosts reporting this CVE, prioritising shared or multi-user systems.Telemetry: DeviceTvmSoftwareVulnerabilities · A local, low-privilege vector matters most where untrusted users can run code. · Rule local-privilege-escalation

Exploitation evidence

  1. Look for low-privileged processes spawning SYSTEM or root-level child processes on affected hosts.Telemetry: DeviceProcessEvents · Hunting hypothesis from the CVSS vector; privilege transitions are a focused starting point, not evidence of attack. · Rule local-privilege-escalation

Response

  1. Confirm the source-stated update on affected hosts.Telemetry: DeviceTvmSoftwareVulnerabilities · Host inventory can verify remediation. · Rule local-privilege-escalation

CISA KEV Record

CISA KEV status was not determined for this record.

Change History & Source Data

— No recorded material change

CNA / source
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Record status · verification
UPDATED · NVD API
CPE
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*, cpe:2.3:o:linux:linux_kernel:2.6.24:-:*:*:*:*:*:*, cpe:2.3:o:linux:linux_kernel:2.6.24:rc3:*:*:*:*:*:*, cpe:2.3:o:linux:linux_kernel:2.6.24:rc4:*:*:*:*:*:*, cpe:2.3:o:linux:linux_kernel:2.6.24:rc5:*:*:*:*:*:*, cpe:2.3:o:linux:linux_kernel:2.6.24:rc6:*:*:*:*:*:*, cpe:2.3:o:linux:linux_kernel:2.6.24:rc7:*:*:*:*:*:*, cpe:2.3:o:linux:linux_kernel:2.6.24:rc8:*:*:*:*:*:*, cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:*, cpe:2.3:o:linux:linux_kernel:7.1:rc2:*:*:*:*:*:*

Evidence & Provenance

3 public sources
git.kernel.orgSource recordnvd.nist.govSource recordgit.kernel.orgSource record

Linked by the query's stored exact CVE association. Review required tables and validation status before use.

Detection Hunting Query
Target: DeviceTvmSoftwareVulnerabilities•Defender XDR
Detect endpoints exposed to CVE-2026-46243
Purpose: Exposure assessment (Category: Exposure Check)Why linked: Query metadata names CVE-2026-46243
DeviceTvmSoftwareVulnerabilities| where CveId == "CVE-2026-46243"| project DeviceId, DeviceName, OSPlatform, OSVersion, SoftwareVendor, SoftwareName, SoftwareVersion, CveId, VulnerabilitySeverityLevel, RecommendedSecurityUpdate, RecommendedSecurityUpdateId| sort by VulnerabilitySeverityLevel desc
Schema Checked · Not runtime validatedSource: SecOps Signal deterministic template · Limited verificationStatic screening: Passed structure and schema checks; tenant execution is not verified.
Open KQL Library

Correlated briefings

— No published briefing references this CVE

SecOps Signal surfaces public advisory facts only. A missing value means the source has not published it, not that your environment is unaffected. No tenant inventory is connected.