Vulnary
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Critical· 9.8official fix available

CVE-2026-64387

A critical double‑free bug was found in the Linux kernel’s SMB client. The flaw can be triggered when a directory query fails and the kernel frees the same memory twice. The issue has been fixed in the kernel source.

publishedJul 25, 2026
last modifiedJul 27, 2026
sourcesNVD
severity · cvss
9.8
critical · how bad it is
exploitation · epss
<1%
37th 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

Linux kernel SMB client, any system running a kernel version before the fix.

02

Real-world impact

If exploited, an attacker could crash the system or execute arbitrary code by causing a double‑free in the SMB client.

03

Why this severity

The CVSS score of 9.8 reflects that the vulnerability is exploitable over the network with no authentication, no user interaction, and can lead to complete compromise of confidentiality, integrity, and availability.

04

What to do about it

official fix available
recommended steps
  1. 01Upgrade the Linux kernel to a version that includes the fix for the SMB client double‑free bug.
  2. 02Reboot the system to load the updated kernel.

NVD-referenced vendor advisory

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 impactHigh
Integrity impactHigh
Availability impactHigh
07

References & 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 →