Cyber Resilience

CVE-2026-64091

Published
19 July 2026
Modified
30 July 2026
CVSS Score v3.1 9.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0055 43th percentile
Risk Priority 70 floored blend · peak EPSS

Summary

CVE-2026-64091 is a critical-severity an unspecified weakness vulnerability in Kernel (inferred from references). Its CVSS base score is 9.8 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 43th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to SI-16 (Memory Protection) and SI-2 (Flaw Remediation) — see the control section below for these in your framework.

EU & UK References

Vulnerability Data

In the Linux kernel, the following vulnerability has been resolved: batman-adv: tt: fix TOCTOU race for reported vlans The local TT based TVLV is generated by first checking the number of VLANs which have at least one TT entry. A…

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new buffer with the correct size for the VLANs is then allocated. Only then, the list of VLANs s used to fill the VLAN entries in the buffer. During this time, the meshif_vlan_list_lock is held. But the actual number of TT entries of each VLAN can still increase during this time - just not the number of VLANs in the list. But the prefilter used in the buffer size calculation might still cause an increase of the number of VLANs which need to be stored. Simply because a VLAN might now suddenly have at least one entry when it had none in the pre-alloc check - and then needs to occupy space which was not allocated. It is better to overestimate the buffer size at the beginning and then fill the buffer only with the VLANs which are not empty.

CWE(s)
None listed

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
attack.mitre.org →
Why these techniques?

Kernel TOCTOU race in batman-adv TT/TVLV handling enables memory corruption exploitable for local/remote privilege escalation via crafted mesh traffic.

Confidence: HIGH · MITRE ATT&CK Enterprise v19.0

Affected Assets

Kernel
—
inferred from references and description; NVD did not file a CPE for this CVE

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)
Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)

—

Validate
Prove the fix (OWASP ASVS)

—

Mitigating Controls (NIST 800-53 r5) AI

SI-2 Flaw Remediation good match
prevent

Directly requires applying the vendor fix that eliminates the TOCTOU window when sizing and populating the VLAN TT TVLV buffer.

SI-16 Memory Protection good match
prevent

Memory protection mechanisms (e.g., hardened allocators, guard pages) block exploitation of the buffer-size miscalculation that can occur during the race.

SC-39 Process Isolation partial match
prevent

Process/kernel isolation limits the blast radius of any memory corruption that results from concurrent modification of the meshif_vlan_list.

References