PT-2026-61406 · Linux · Linux

CVE-2026-64089 · Published 2026-07-19 · Updated 2026-07-19

NVD

CVSS v3.1

9.8

Critical

Base vector

AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

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().

Fix

Related Identifiers

CVE-2026-64089

Affected Products

Linux

References · 9

• https://nvd.nist.gov/vuln/detail/CVE-2026-64089 · Security Note
• https://git.kernel.org/stable/c/d29abf70c665730e249d2ec8e1402095ae26bcee · Note
• https://git.kernel.org/stable/c/fc92cdfcb295cefa4344d71a527d61b638b7bfc4 · Note
• https://git.kernel.org/stable/c/22d59c72f4a47ffec121d0610f70d0d70c3c11c8 · Note
• https://git.kernel.org/stable/c/55dc41fe8821e9a849e147255ad572bc933a9d15 · Note
• https://git.kernel.org/stable/c/c424e8519ac78eac5d9f4eecf06208a0d619ec14 · Note
• https://git.kernel.org/stable/c/6314089acf0ddf64376fdc0b1420695504c73f52 · Note
• https://git.kernel.org/stable/c/179eb62506a02d00370bd6478898cb632e10986c · Note
• https://git.kernel.org/stable/c/eb235472b52ef36981c5aad330485eaf2382c53b · Note