Vulnary
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Critical· 9.8official fix available

CVE-2026-64091

A critical race condition in the Linux kernel’s batman‑adv module can let a local attacker manipulate VLAN reporting. The flaw occurs when the kernel allocates a buffer for VLAN entries based on a pre‑check that can become outdated, leading to a time‑of‑check to time‑of‑use bug. The issue has been fixed in the kernel.

publishedJul 19, 2026
last modifiedJul 30, 2026
sourcesNVD
severity · cvss
9.8
critical · how bad it is
exploitation · epss
<1%
43th 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 19, 2026

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

01

Who is affected

Linux kernel users running the batman‑adv networking module, especially those using the TT‑based TVLV feature. The specific kernel versions are not listed, but any kernel that includes the unpatched batman‑adv component is affected.

02

Real-world impact

An attacker with local access could cause incorrect VLAN reporting, potentially leading to denial of service or misconfigured network traffic.

03

Why this severity

The CVSS score of 9.8 reflects that the vulnerability is exploitable from any network, requires no privileges, and can compromise 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 batman‑adv patch that fixes the TOCTOU race.
  2. 02Restart the system or reload the kernel module to apply the update.

NVD description indicates a fix has been applied.

05

Timeline

  1. Jul 19, 2026 · 14d ago
    Published
    Disclosed and added to the National Vulnerability Database.
  2. Jul 20, 2026 · 13d ago
    Official fix available
    A vendor patch or mitigation now exists — see the remediation steps above.
  3. Jul 30, 2026 · 3d ago
    Advisory updated
    The NVD record was last revised.
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

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 →