CVE-2026-23519

Name: CVE-2026-23519
Creator: NVD / NIST
Published: 2026-01-15T20:16:05.313+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 8.9/10EPSS 0.50%

Last modified Jun 17, 2026

CVE-2026-23519 is a high-severity vulnerability rated 8.9/10 on the CVSS scale. RustCrypto CMOV provides conditional move CPU intrinsics which are guaranteed on major platforms to execute in constant-time and not be rewritten as branches by the compiler. Prior to 0.4.4, the thumbv6m-none-eabi (Cortex M0, M0+ and M1) compiler emits non-constant time assembly when using cmovnz (portable version). EPSS estimates a 0.50% chance of exploitation in the next 30 days.

Description

RustCrypto CMOV provides conditional move CPU intrinsics which are guaranteed on major platforms to execute in constant-time and not be rewritten as branches by the compiler. Prior to 0.4.4, the thumbv6m-none-eabi (Cortex M0, M0+ and M1) compiler emits non-constant time assembly when using cmovnz (portable version). This vulnerability is fixed in 0.4.4.

Metrics

CVSS 3.1

9.8/10

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

CVSS 4.0

8.9/10

CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS Probability

0.50%

38.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Rustcrypto	Cmov	< 0.4.4

References

https://github.com/RustCrypto/utils/commit/55977257e7c82a309d5e8abfdd380a774f0f9778Patch
https://github.com/RustCrypto/utils/security/advisories/GHSA-2gqc-6j2q-83qpExploit, Vendor Advisory
https://github.com/RustCrypto/utils/security/advisories/GHSA-2gqc-6j2q-83qpExploit, Vendor Advisory

Timeline

Published: Jan 15, 2026
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-23519?

How severe is CVE-2026-23519?

CVE-2026-23519 has a CVSS score of 8.9/10 (HIGH severity). The EPSS model estimates a 0.50% probability of exploitation in the next 30 days.

How do I fix CVE-2026-23519?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-23519?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST