Integer overflow in Linux kernel - CVE-2026-63836
Published: July 20, 2026
Vulnerability identifier: #VU138818
CSH Severity: Low
CVSS v4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-63836
CWE-ID: CWE-190
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a local user to cause a denial of service.
The vulnerability exists due to an integer overflow leading to divide-by-zero in batadv_tp_update_cwnd() in the batman-adv tp_meter component when processing crafted acknowledgment traffic. A local user can trigger the vulnerable calculation to cause a denial of service.
The issue occurs when the congestion window reaches 0x20000000, causing a left shift in the divisor to wrap to zero under 32-bit arithmetic.
Affected software
Linux kernel
How to mitigate CVE-2026-63836
Install security update from vendor's repository.
Linux kernel - update to 7.0 rc3
External References
- https://git.kernel.org/stable/c/1381b021bf886b793fa5ffb895a8efae7ba0318f
- https://git.kernel.org/stable/c/33ccd52f3cc9ed46ce395199f89aa3234dc83314
- https://git.kernel.org/stable/c/35264c4d46067d6312871488c810cef387f8c1f6
- https://git.kernel.org/stable/c/585616dab0aa9c45bc11b2c8082ca78533bc00e9
- https://git.kernel.org/stable/c/7d2a44bc6bbe39aed03c68864aa0e54e04a50278
- https://git.kernel.org/stable/c/ac229c86e49fdb96d91f51bc2fa37a9c4f58c44f
- https://git.kernel.org/stable/c/cd74176cf1685f35a2e5f212d15748bbfecb53b6
- https://git.kernel.org/stable/c/d08b69da40a101df1e28bfe1e8fa7a09ffa41107