---
id: CVE-2026-64313
title: |-
  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 ov…
summary: |-
  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 ov…
severity: high
cvss: 8.8
cvssVector: 'CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
published: '2026-07-25'
updated: '2026-07-27'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-64313'
references:
  - url: 'https://git.kernel.org/stable/c/24a54dfa06d09813b4802a374fad3d2c0e16a884'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/27b536a2ec8e2f85a0380c2d13c9ecbc7aaab406'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/5275e0fca256d081e2e7d4ba3dd8216c6e50d44e'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/677450e5ef850c4d28b7956aa01104548c2a894e'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/774ddddf5eb26eeca177350413e3e2bc50930ee9'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/b709e0e768766abe29a49e1c1922a1604be602f4'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/d11b2bb99bec1f5557c01cac42231e23745f49b8'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/ebaae7c4251cc0cdb2602f334d4f08a3e82d271e'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
epss: 0.00354
epssPercentile: 0.29209
ingestedAt: '2026-07-27T06:16:50.372Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.