CVE-2026-64091
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 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.
Affected versions
Linux kernel versions
3.16.60,
4.4.217,
4.9.217,
4.14.174,
4.17
and later are affected. Fixed in
5.10.259,
5.15.210,
6.1.176,
6.6.143,
6.12.93,
6.18.34,
7.0.11,
7.1
and their respective stable series.
References
8 totalFrequently asked questions
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What is CVE-2026-64091?
CVE-2026-64091 is a unscored severity Linux kernel vulnerability . It affects Linux kernel versions from 3.16.60 onward and has been patched in 5.10.259, 5.15.210, 6.1.176 and others. CVE-2026-64091 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
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Is there a patch available for CVE-2026-64091?
Yes — CVE-2026-64091 has been patched. Fixed versions include 5.10.259, 5.15.210, 6.1.176 and others. If you are running Linux kernel 3.16.60 or later up to the fix versions, apply the relevant patch for your kernel branch.
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Is CVE-2026-64091 actively exploited?
No — CVE-2026-64091 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.