CVE-2026-64313

Analyzed Analyzed - Analysis Complete

ECC Carry Overflow in Linux Kernel Crypto

Publication date: 2026-07-25

Last updated on: 2026-09-03

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

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Meta Information

Published

2026-07-25

Last Modified

2026-09-03

Generated

2026-09-03

AI Q&A

2026-07-25

EPSS Evaluated

2026-09-02

NVD

CVE-2026-64313

EUVD

EUVD-2026-49025

Affected Vendors & Products

Vendor	Product	Version / Range
linux	linux_kernel	From 5.11 (inc) to 5.15.212 (exc)
linux	linux_kernel	From 5.16 (inc) to 6.1.178 (exc)
linux	linux_kernel	From 6.2 (inc) to 6.6.145 (exc)
linux	linux_kernel	From 6.7 (inc) to 6.12.96 (exc)
linux	linux_kernel	From 6.13 (inc) to 6.18.39 (exc)
linux	linux_kernel	From 6.19 (inc) to 7.1.4 (exc)
linux	linux_kernel	From 4.8 (inc) to 5.10.261 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-190	The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.

Attack-Flow Graph

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.

Compliance Impact

This vulnerability is a low-level cryptographic flaw in the Linux kernel's ECC (Elliptic Curve Cryptography) implementation. It does not directly impact compliance with standards like GDPR or HIPAA, as those focus on data protection, privacy, and security controls rather than specific cryptographic implementation details.

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.

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