Critical 9.8Published Jul 19, 2026

CVE-2026-64089batman-adv: tt: fix negative last_changeset_len

Updated under an hour ago (Oct 26, 2026, 1:23 PM ET)

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Exploited in the last 30 days

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().

CVSS: 9.8 CRITICAL (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness (CWE): Not given
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Linux
NVD analysis: Analyzed
Record last updated: Aug 5, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Linux Linux linux:linux (from the name)	from a73105b8d4c765d9ebfb664d0a66802127d8e4c7 before 6314089acf0ddf64376fdc0b1420695504c73f52; from a73105b8d4c765d9ebfb664d0a66802127d8e4c7 before 55dc41fe8821e9a849e147255ad572bc933a9d15; from a73105b8d4c765d9ebfb664d0a66802127d8e4c7 before c424e8519ac78eac5d9f4eecf06208a0d619ec14; from a73105b8d4c765d9ebfb664d0a66802127d8e4c7 before 22d59c72f4a47ffec121d0610f70d0d70c3c11c8; from a73105b8d4c765d9ebfb664d0a66802127d8e4c7 before eb235472b52ef36981c5aad330485eaf2382c53b; from a73105b8d4c765d9ebfb664d0a66802127d8e4c7 before 179eb62506a02d00370bd6478898cb632e10986c; from a73105b8d4c765d9ebfb664d0a66802127d8e4c7 before d29abf70c665730e249d2ec8e1402095ae26bcee; from a73105b8d4c765d9ebfb664d0a66802127d8e4c7 before fc92cdfcb295cefa4344d71a527d61b638b7bfc4	CNA record
linux linux_kernel linux:linux_kernel	from 3.1 before 5.10.258; from 5.11 before 5.15.209; from 5.16 before 6.1.175; from 6.2 before 6.6.142; from 6.7 before 6.12.92; from 6.13 before 6.18.34; from 6.19 before 7.0.11; 7.1; and 3 more ranges	NVD

References

References

https://git.kernel.org/stable/c/6314089acf0ddf64376fdc0b1420695504c73f52	patch
https://git.kernel.org/stable/c/55dc41fe8821e9a849e147255ad572bc933a9d15	patch
https://git.kernel.org/stable/c/c424e8519ac78eac5d9f4eecf06208a0d619ec14	patch
https://git.kernel.org/stable/c/22d59c72f4a47ffec121d0610f70d0d70c3c11c8	patch
https://git.kernel.org/stable/c/eb235472b52ef36981c5aad330485eaf2382c53b	patch
https://git.kernel.org/stable/c/179eb62506a02d00370bd6478898cb632e10986c	patch
https://git.kernel.org/stable/c/d29abf70c665730e249d2ec8e1402095ae26bcee	patch
https://git.kernel.org/stable/c/fc92cdfcb295cefa4344d71a527d61b638b7bfc4	patch

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.