CVE-2021-36647

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.

• CWE-327
• CWE-327

• https://github.com/ARMmbed/mbedtls/releases/Third Party Advisory
• https://kouzili.com/Load-Step.pdfThird Party Advisory
• https://tls.mbed.org/tech-updates/security-advisories/mbedtls-security-advisory-2021-07-1Vendor Advisory
• https://github.com/ARMmbed/mbedtls/releases/Third Party Advisory
• https://kouzili.com/Load-Step.pdfThird Party Advisory
• https://lists.debian.org/debian-lts-announce/2025/06/msg00034.html
• https://tls.mbed.org/tech-updates/security-advisories/mbedtls-security-advisory-2021-07-1Vendor Advisory

Published

Jan 17, 2023

Last Modified

Jun 17, 2026

Status

Modified

• How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
• Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
• PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
• AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.

• CVE-2021-36628Rejected reason: DO NOT USE THIS CANDIDATE NUMBER. ConsultID…
• CVE-2021-3663firefly-iii is vulnerable to Improper Restriction of Excessi…7.5
• CVE-2021-36630DDOS reflection amplification vulnerability in eAut module o…7.5
• CVE-2021-36631Untrusted search path vulnerability in Baidunetdisk Version …6.7
• CVE-2021-3664url-parse is vulnerable to URL Redirection to Untrusted Site5.3
• CVE-2021-36646A Cross Site Scrtpting (XSS) vulnerability in KodExplorer 4.…6.1
• CVE-2021-36654CMSuno 1.7 is vulnerable to an authenticated stored cross si…5.4
• CVE-2021-3666body-parser-xml is vulnerable to Improperly Controlled Modif…9.8
• CVE-2021-36665An issue was discovered in Druva 6.9.0 for macOS, allows att…7.8
• CVE-2021-36666An issue was discovered in Druva 6.9.0 for MacOS, allows att…7.8
• CVE-2021-36667Command injection vulnerability in Druva inSync 6.9.0 for Ma…7.8
• CVE-2021-36668URL injection in Driva inSync 6.9.0 for MacOS, allows attack…7.8