PT-2026-3096 · Unknown · Rust-Crypto

Nicstr · Published 2026-01-14 · Updated 2026-01-15 · CVE-2026-23519

Positive Technologies (AI Summary)

CVSS v3.1

9.8

Critical

Base vector

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

Name of the Vulnerable Software and Affected Versions RustCrypto versions prior to 0.4.4

Description The RustCrypto CMOV implementation, designed to provide constant-time conditional move operations, exhibits non-constant time behavior when compiled for the thumbv6m-none-eabi target (Cortex M0, M0+, and M1 processors). This occurs due to an LLVM optimization pass interpreting a bitwise operation as a conditional branch, negating the constant-time guarantee. The issue arises during the mask computation within the cmov crate, specifically related to the bitnz function and its subsequent use in a wrapping subtraction. The portable version of cmovnz is affected. The impact of this issue is currently unclear, but the cmov crate provides a warning to users that the portable version is best-effort.

Recommendations Update to RustCrypto version 0.4.4 or later.

Exploit

Fix

Side Channel Attack

Weakness Enumeration

CWE-208

CWE-203

Related Identifiers

CVE-2026-23519

GHSA-2GQC-6J2Q-83QP

RUSTSEC-2026-0003

Affected Products

Rust-Crypto

References · 11

• 🔥 https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/23xxx/CVE-2026-23519.json · Exploit
• 🔥 https://github.com/RustCrypto/utils/security/advisories/GHSA-2gqc-6j2q-83qp · Exploit
• https://github.com/RustCrypto/utils/commit/55977257e7c82a309d5e8abfdd380a774f0f9778 · Patch
• https://osv.dev/vulnerability/CVE-2026-23519 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-23519 · Security Note
• https://osv.dev/vulnerability/RUSTSEC-2026-0003 · Vendor Advisory
• https://osv.dev/vulnerability/GHSA-2gqc-6j2q-83qp · Vendor Advisory
• https://github.com/RustCrypto/utils · Note
• https://crates.io/crates/cmov · Note
• https://twitter.com/CVEnew/status/2011926063891563011 · Twitter Post
• https://rustsec.org/advisories/RUSTSEC-2026-0003.html · Note