{"id":"CVE-2021-36647","details":"Use of a Broken or Risky Cryptographic Algorithm in the function mbedtls_mpi_exp_mod() in lignum.c in Mbed TLS Mbed TLS all versions before 3.0.0, 2.27.0 or 2.16.11 allows attackers with access to precise enough timing and memory access information (typically an untrusted operating system attacking a secure enclave such as SGX or the TrustZone secure world) to recover the private keys used in RSA.","modified":"2026-04-10T04:35:38.500183Z","published":"2023-01-17T21:15:10.880Z","references":[{"type":"WEB","url":"https://lists.debian.org/debian-lts-announce/2025/06/msg00034.html"},{"type":"ADVISORY","url":"https://github.com/ARMmbed/mbedtls/releases/"},{"type":"ADVISORY","url":"https://kouzili.com/Load-Step.pdf"},{"type":"ADVISORY","url":"https://tls.mbed.org/tech-updates/security-advisories/mbedtls-security-advisory-2021-07-1"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/armmbed/mbedtls","events":[{"introduced":"0"},{"fixed":"aa1d4e097342af799ba80dfb13640efef498227c"},{"introduced":"3f8d78411a26e833db18d9fbde0e2f0baeda87f0"},{"fixed":"f71e2878084126737cc39083e1e15afc459bd93d"},{"introduced":"8b3f26a5ac38d4fdccbc5c5366229f3e01dafcc0"},{"fixed":"8df2f8e7b9c7bb9390ac74bb7bace27edca81a2b"}],"database_specific":{"versions":[{"introduced":"0"},{"fixed":"2.16.11"},{"introduced":"2.17.0"},{"fixed":"2.27.0"},{"introduced":"2.28.0"},{"fixed":"3.0.0"}]}}],"versions":["beta-oob-2","mbedos-release-15-11","mbedos-techcon-oob2","mbedtls-2.0.0","mbedtls-2.1.0","mbedtls-2.1.1","mbedtls-2.1.2","mbedtls-2.10.0","mbedtls-2.11.0","mbedtls-2.12.0","mbedtls-2.13.0","mbedtls-2.13.1","mbedtls-2.14.0","mbedtls-2.16.0","mbedtls-2.16.10","mbedtls-2.16.2","mbedtls-2.16.3","mbedtls-2.16.4","mbedtls-2.16.5","mbedtls-2.16.6","mbedtls-2.16.8","mbedtls-2.16.9","mbedtls-2.19.0","mbedtls-2.19.0d1","mbedtls-2.19.0d2","mbedtls-2.19.1","mbedtls-2.2.0","mbedtls-2.2.1","mbedtls-2.20.0","mbedtls-2.20.0d0","mbedtls-2.21.0","mbedtls-2.22.0d0","mbedtls-2.24.0","mbedtls-2.26.0","mbedtls-2.3.0","mbedtls-2.4.0","mbedtls-2.5.0","mbedtls-2.5.1","mbedtls-2.6.0","mbedtls-2.6.0-rc1","mbedtls-2.7.0","mbedtls-2.7.0-rc1","mbedtls-2.8.0","mbedtls-2.8.0-rc1","mbedtls-2.9.0","polarssl-1.2.0","polarssl-1.2.1","polarssl-1.2.2","polarssl-1.2.4","polarssl-1.2.5","polarssl-1.2.6","polarssl-1.3.0","polarssl-1.3.0-rc0","polarssl-1.3.1","polarssl-1.3.2","polarssl-1.3.3","polarssl-1.3.4","polarssl-1.3.5","polarssl-1.3.6","polarssl-1.3.7","polarssl-1.3.8","polarssl-1.3.9","v2.16.10","v2.16.8","v2.16.9","v2.24.0","v2.26.0","yotta-2.3.1"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-36647.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N"}]}