CVE-2026-64313: Linux Kernel

High severity, CVSS 8.8. EPSS: 0.4% chance of exploitation in the next 30 days.

In the Linux kernel, the following vulnerability has been resolved: crypto: ecc - Fix carry overflow in vli multiplication The carry flag calculation fails when r01.m_high is saturated (0xFFFFFFFFFFFFFFFF) and addition of lower bits overflows. The condition (r01.m_high < product.m_high) doesn't handle the case where r01.m_high == product.m_high and an additional carry exists from lower-bit overflow. When commit 3c4b23901a0c ("crypto: ecdh - Add ECDH software support") introduced crypto/ecc.c, it split the muladd() function in the micro-ecc library into separate mul_64_64() and add_128_128() helpers. It seems the check got lost in translation. Add proper handling for this boundary by accounting for the carry from the lower addition.

Affected products

• Linux Linux Kernel: from 4.8, before 5.10.261 (fixed in 5.10.261); from 5.11, before 5.15.212 (fixed in 5.15.212); from 5.16, before 6.1.178 (fixed in 6.1.178); from 6.2, before 6.6.145 (fixed in 6.6.145); from 6.7, before 6.12.96 (fixed in 6.12.96); from 6.13, before 6.18.39 (fixed in 6.18.39); …

Published 2026-07-25. Last modified 2026-09-03.