SEPTEMBER 7, 2026
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Case File

CVE-2026-64089

CRITICAL · CVSS 9.8 EPSS 0.55%

Source: NVD + CISA KEV + EPSS · Published 2026-07-19 · Last synced 2026-08-18

CyberRota Analysis

AI-Generated

The vulnerability affects the Linux kernel's batman-adv module, where an incorrect handling of the `last_changeset_len` field can lead to buffer allocation issues due to negative integer wrapping. This flaw may allow an attacker to exploit uninitialized memory, potentially leading to information disclosure or arbitrary code execution. Organizations using affected versions of the Linux kernel, particularly those relying on the batman-adv networking protocol, should prioritize patching this critical vulnerability.

CVE
CVE-2026-64089
Severity
CRITICAL
CVSS
9.8
EPSS
0.55%
Linux

Original NVD Description

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().

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