Vulnary
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Critical· 9.1official fix available

CVE-2026-64392

A critical vulnerability in the Linux kernel's ksmbd component allows attackers to bypass filesystem permission checks during file deletion, potentially leading to unauthorized data removal or modification. The issue arises from using worker credentials instead of user credentials when closing files marked for deletion.

publishedJul 25, 2026
last modifiedJul 27, 2026
sourcesNVD
severity · cvss
9.1
critical · how bad it is
exploitation · epss
<1%
38th percentile · chance of exploitation in 30 days
(ai-assisted) A model wrote this summary from the official data, so double-check it against the source before you act on it. Read the official advisory →
auto-deletes from the system
counting…on Aug 26, 2026

An official fix is available, so this entry is kept for 30 days and then removed automatically.

01

Who is affected

Systems using the Linux kernel with the ksmbd component (e.g., Samba file servers)

02

Real-world impact

High risk of unauthorized data manipulation or deletion if exploited

03

Why this severity

CVSS 9.1 (critical): High integrity and availability impact with no privileges required

04

What to do about it

official fix available
recommended steps
  1. 011. Update your Linux kernel to the patched version that includes the fix for CVE-2026-64392.
  2. 022. Apply the kernel update through your distribution's package manager or vendor instructions.

NVD description of kernel vulnerability resolution

05

Timeline

  1. Jul 25, 2026 · 7d ago
    Published
    Disclosed and added to the National Vulnerability Database.
  2. Jul 27, 2026 · 5d ago
    Official fix available
    A vendor patch or mitigation now exists — see the remediation steps above.
06

How it’s attacked

Attack vectorNetwork (remote)
Attack complexityLow
Privileges requiredNone
User interactionNone needed
ScopeUnchanged
Confidentiality impactNone
Integrity impactHigh
Availability impactHigh
07

References & advisories

NVD advisory ↗Search advisories ↗
(ai-assisted) A model wrote this summary from the official data, so double-check it against the source before you act on it. Read the official advisory →