CVE-2026-64313
Received Received - Intake

ECC Carry Overflow in Linux Kernel Crypto

Publication date: 2026-07-25

Last updated on: 2026-07-25

Assigner: kernel.org

Description
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.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published
2026-07-25
Last Modified
2026-07-25
Generated
2026-07-25
AI Q&A
2026-07-25
EPSS Evaluated
N/A
NVD
CVE-2026-64313
EUVD
EUVD-2026-49025

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
linux_kernel linux_kernel *

Helpful Resources

Exploitability

CWE
CWE Icon
KEV
KEV Icon
CWE ID Description
CWE-UNKNOWN

Attack-Flow Graph

AI Quick Actions

Instant insights powered by AI
Executive Summary

This vulnerability is in the Linux kernel's cryptographic module for elliptic curve cryptography (ECC). It involves a flaw in the carry flag calculation during multiplication operations in the vli (very long integer) module. Specifically, the issue occurs when the high part of a value saturates at its maximum (0xFFFFFFFFFFFFFFFF) and an overflow happens in the lower bits during addition. The current check fails to account for cases where the high parts are equal but a carry exists from the lower bits.

Detection Guidance

This vulnerability is specific to the Linux kernel's cryptographic subsystem and does not have network-based detection methods. It requires checking the kernel version and examining the crypto/ecc.c file for the affected mul_64_64() and add_128_128() functions. Use commands like 'uname -a' to check kernel version and 'grep' to inspect the source code for the vulnerable functions.

Impact Analysis

This vulnerability could potentially allow an attacker to exploit weaknesses in cryptographic operations that rely on ECC, such as key generation or digital signatures. If exploited, it might lead to incorrect cryptographic results, data corruption, or security breaches in systems using affected Linux kernel versions.

Mitigation Strategies

Update your Linux kernel to the latest stable version that includes the fix for this vulnerability. If you are using a distribution with a patched kernel, apply the security updates immediately. Monitor vendor advisories for kernel updates addressing CVE-2026-64313.

Chat Assistant

Ask questions about this CVE
Hi! I’m here to help you understand CVE-2026-64313. Ask me anything about the vulnerability, its impact, or mitigation strategies.
0/70

EPSS Chart