CVE-2026-64313 (CVSS 8.8)

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.

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CVSS v3.1 Score

8.8

HIGH

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0035

Probability of exploitation

0.27%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

References

Other References

https://git.kernel.org/stable/c/24a54dfa06d09813b4802a374fad3d2c0e16a884 https://git.kernel.org/stable/c/27b536a2ec8e2f85a0380c2d13c9ecbc7aaab406 https://git.kernel.org/stable/c/5275e0fca256d081e2e7d4ba3dd8216c6e50d44e https://git.kernel.org/stable/c/677450e5ef850c4d28b7956aa01104548c2a894e https://git.kernel.org/stable/c/774ddddf5eb26eeca177350413e3e2bc50930ee9 https://git.kernel.org/stable/c/b709e0e768766abe29a49e1c1922a1604be602f4 https://git.kernel.org/stable/c/d11b2bb99bec1f5557c01cac42231e23745f49b8 https://git.kernel.org/stable/c/ebaae7c4251cc0cdb2602f334d4f08a3e82d271e

Frequently Asked Questions

What is CVE-2026-64313? +

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. It has a CVSS v3.1 base score of 8.8 (HIGH).

How severe is CVE-2026-64313? +

CVE-2026-64313 has a CVSS v3.1 score of 8.8 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0035, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-64313? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

CVE-2026-64313