{"id":"CVE-2026-23519","state":"PUBLISHED","title":"RustCrypto cmov: thumbv6m-none-eabi compiler emits non-constant time assembly when using cmovnz","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.","publishedAt":"2026-01-15T19:13:54.440Z","updatedAt":"2026-01-15T19:57:48.741Z","severity":{"score":8.9,"label":"High","version":"4.0","vector":"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","source":"GitHub_M"},"assigner":"GitHub_M","products":["RustCrypto utils"],"affected":[{"vendor":"RustCrypto","product":"utils","versions":[{"version":"< 0.4.4","status":"affected"}]}],"references":["https://github.com/RustCrypto/utils/security/advisories/GHSA-2gqc-6j2q-83qp","https://github.com/RustCrypto/utils/commit/55977257e7c82a309d5e8abfdd380a774f0f9778"],"weaknesses":["CWE-208"],"ingestedAt":"2026-10-29T20:11:21.040Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/23xxx/CVE-2026-23519.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-23519","state":"PUBLISHED","datePublished":"2026-01-15T19:13:54.440Z","dateUpdated":"2026-01-15T19:57:48.741Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-01-13T18:22:43.980Z"},"containers":{"cna":{"title":"RustCrypto cmov: thumbv6m-none-eabi compiler emits non-constant time assembly when using cmovnz","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."}],"affected":[{"vendor":"RustCrypto","product":"utils","versions":[{"version":"< 0.4.4","status":"affected"}]}],"references":[{"url":"https://github.com/RustCrypto/utils/security/advisories/GHSA-2gqc-6j2q-83qp","name":"https://github.com/RustCrypto/utils/security/advisories/GHSA-2gqc-6j2q-83qp","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/RustCrypto/utils/commit/55977257e7c82a309d5e8abfdd380a774f0f9778","name":"https://github.com/RustCrypto/utils/commit/55977257e7c82a309d5e8abfdd380a774f0f9778","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"HIGH","attackRequirements":"NONE","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"HIGH","vulnIntegrityImpact":"NONE","vulnAvailabilityImpact":"NONE","subConfidentialityImpact":"HIGH","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","baseScore":8.9,"baseSeverity":"HIGH","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","version":"4.0"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-208","lang":"en","description":"CWE-208: Observable Timing Discrepancy","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-01-15T19:13:54.440Z"},"source":{"advisory":"GHSA-2gqc-6j2q-83qp","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/RustCrypto/utils/security/advisories/GHSA-2gqc-6j2q-83qp","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-01-15T19:57:42.346432Z","id":"CVE-2026-23519","options":[{"Exploitation":"poc"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-01-15T19:57:48.741Z"}}]}}}