CVE-2026-64089
In the Linux kernel, the following vulnerability has been resolved: batman-adv: tt: fix negative last_changeset_len batadv_piv_tt::last_changeset_len len was declared as s16, but the field is never intended to hold a negative value. When a value greater than 32767 is assigned, it wraps to a negative signed integer. In batadv_send_my_tt_response(), last_changeset_len is temporarily widened to s32. The incorrectly negative s16 value propagates into the s32, causing batadv_tt_prepare_tvlv_local_data() to allocate a full sized buffer but populates only a small portion of it with the collected changeset. All remaining bits are kept uninitialized. Using an u16 avoids this type confusion and ensures that no (negative) sign extension is performed in batadv_send_my_tt_response().
Affected versions
Linux kernel versions
3.1
and later are affected. Fixed in
5.10.258,
5.15.209,
6.1.175,
6.6.142,
6.12.92,
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-2026-64089?
CVE-2026-64089 is a unscored severity Linux kernel vulnerability . It affects Linux kernel versions from 3.1 onward and has been patched in 5.10.258, 5.15.209, 6.1.175 and others. CVE-2026-64089 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-2026-64089?
Yes — CVE-2026-64089 has been patched. Fixed versions include 5.10.258, 5.15.209, 6.1.175 and others. If you are running Linux kernel 3.1 or later up to the fix versions, apply the relevant patch for your kernel branch.
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Is CVE-2026-64089 actively exploited?
No — CVE-2026-64089 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.