CVE-2026-23519

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.

CVSS v3 9.8 CRITICAL

9.8^/10

CVSS v3 : CRITICAL

Vector :

Exploitability : 3.9 / Impact : 5.9

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://github.com/RustCrypto/utils/commit/55977257e7c82a309d5e8abfdd380a774f0f9778	Patch
https://github.com/RustCrypto/utils/security/advisories/GHSA-2gqc-6j2q-83qp	Exploit Vendor Advisory
https://github.com/RustCrypto/utils/security/advisories/GHSA-2gqc-6j2q-83qp	Exploit Vendor Advisory

Configurations

Configuration 1 (hide)

cpe:2.3:a:rustcrypto:cmov:*:*:*:*:*:rust:*:*

History

23 Jan 2026, 18:59

Type	Values Removed	Values Added
References	~~() https://github.com/RustCrypto/utils/commit/55977257e7c82a309d5e8abfdd380a774f0f9778 -~~	() https://github.com/RustCrypto/utils/commit/55977257e7c82a309d5e8abfdd380a774f0f9778 - Patch
References	~~() https://github.com/RustCrypto/utils/security/advisories/GHSA-2gqc-6j2q-83qp -~~	() https://github.com/RustCrypto/utils/security/advisories/GHSA-2gqc-6j2q-83qp - Exploit, Vendor Advisory
CPE		cpe:2.3:a:rustcrypto:cmov::::::rust::*
CWE		CWE-203
CVSS	v2 : ~~unknown~~ v3 : ~~unknown~~	v2 : unknown v3 : 9.8
First Time		Rustcrypto cmov Rustcrypto

15 Jan 2026, 20:16

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-01-15 20:16

Updated : 2026-01-23 18:59

NVD link : CVE-2026-23519

Mitre link : CVE-2026-23519

CVE.ORG link : CVE-2026-23519

JSON object : View

Products Affected

rustcrypto

cmov

CWE

CWE-208

Observable Timing Discrepancy

CWE-203

Observable Discrepancy

{"id": "CVE-2026-23519", "cveTags": [], "metrics": {"cvssMetricV31": [{"type": "Primary", "source": "nvd@nist.gov", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 9.8, "attackVector": "NETWORK", "baseSeverity": "CRITICAL", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "NONE", "confidentialityImpact": "HIGH"}, "impactScore": 5.9, "exploitabilityScore": 3.9}], "cvssMetricV40": [{"type": "Secondary", "source": "security-advisories@github.com", "cvssData": {"Safety": "NOT_DEFINED", "version": "4.0", "Recovery": "NOT_DEFINED", "baseScore": 8.9, "Automatable": "NOT_DEFINED", "attackVector": "NETWORK", "baseSeverity": "HIGH", "valueDensity": "NOT_DEFINED", "vectorString": "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", "exploitMaturity": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED", "userInteraction": "NONE", "attackComplexity": "HIGH", "attackRequirements": "NONE", "privilegesRequired": "NONE", "subIntegrityImpact": "NONE", "vulnIntegrityImpact": "NONE", "integrityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "vulnAvailabilityImpact": "NONE", "availabilityRequirement": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "subConfidentialityImpact": "HIGH", "vulnConfidentialityImpact": "HIGH", "confidentialityRequirement": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED"}}]}, "published": "2026-01-15T20:16:05.313", "references": [{"url": "https://github.com/RustCrypto/utils/commit/55977257e7c82a309d5e8abfdd380a774f0f9778", "tags": ["Patch"], "source": "security-advisories@github.com"}, {"url": "https://github.com/RustCrypto/utils/security/advisories/GHSA-2gqc-6j2q-83qp", "tags": ["Exploit", "Vendor Advisory"], "source": "security-advisories@github.com"}, {"url": "https://github.com/RustCrypto/utils/security/advisories/GHSA-2gqc-6j2q-83qp", "tags": ["Exploit", "Vendor Advisory"], "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Primary", "source": "security-advisories@github.com", "description": [{"lang": "en", "value": "CWE-208"}]}, {"type": "Primary", "source": "nvd@nist.gov", "description": [{"lang": "en", "value": "CWE-203"}]}], "descriptions": [{"lang": "en", "value": "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."}], "lastModified": "2026-01-23T18:59:58.223", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:rustcrypto:cmov:*:*:*:*:*:rust:*:*", "vulnerable": true, "matchCriteriaId": "A05B5CBC-9FDB-429A-889F-56928657A4D8", "versionEndExcluding": "0.4.4"}], "operator": "OR"}]}], "sourceIdentifier": "security-advisories@github.com"}