CVE-2026-10512: The X25519 x86_64 assembly implementation fails to clear the most significant bit during the final modular reduction, so the computed result may not be fully reduced modulo the fie

highCVSS 7.5CVE-2026-10512

The X25519 x86_64 assembly implementation fails to clear the most significant bit during the final modular reduction, so the computed result may not be fully reduced modulo the field prime 2^255 - 19. This can leave the field element in a non-canonical form, producing an incorrect result from the scalar multiplication and potentially a wrong shared secret. The final carry-propagation chains in the x64 and AVX2 reduction routines could overflow into the top bit, and the high limb was not masked afterward, so the 255-bit field element was left non-canonical.

Details

Source: NVD Recent CVEs (US · database · site)
Severity: high — CVSS 7.5
Published: 2026-06-25
Last updated: 2026-06-26
Exploitation: Not in CISA KEV at last sync

Original advisory: https://nvd.nist.gov/vuln/detail/CVE-2026-10512

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2026-105120.26% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 18% of all scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-10512	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

highCVE-2026-10512: X25519 x86_64 assembly final reduction leaves non-canonical field elementmsrc

Recent advisories for X25519 x86_64 assembly

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

highCVE-2026-10512: X25519 x86_64 assembly final reduction leaves non-canonical field elementmsrc · 2026-06-09