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().

CVSS v3 9.8 CRITICAL

9.8^/10

CVSS v3 : CRITICAL

Vector :

Exploitability : 3.9 / Impact : 5.9

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope UNCHANGED

References

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

Configurations

No configuration.

History

20 Jul 2026, 15:17

Type	Values Removed	Values Added
CVSS	v2 : ~~unknown~~ v3 : ~~unknown~~	v2 : unknown v3 : 9.8

19 Jul 2026, 16:17

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-07-19 16:17

Updated : 2026-07-20 15:17

NVD link : CVE-2026-64089

Mitre link : CVE-2026-64089

CVE.ORG link : CVE-2026-64089

JSON object : View

Products Affected

No product.

CWE

No CWE.

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When a value greater than 32767 is\nassigned, it wraps to a negative signed integer.\n\nIn batadv_send_my_tt_response(), last_changeset_len is temporarily widened\nto s32. The incorrectly negative s16 value propagates into the s32, causing\nbatadv_tt_prepare_tvlv_local_data() to allocate a full sized buffer but\npopulates only a small portion of it with the collected changeset. All\nremaining bits are kept uninitialized.\n\nUsing an u16 avoids this type confusion and ensures that no (negative) sign\nextension is performed in batadv_send_my_tt_response()."}], "lastModified": "2026-07-20T15:17:08.147", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}