Vulnerability in Arm Mbed TLS
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.
Vulnerability class: POODLE (CVE-2014-3566)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 4.7 (Medium). Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N.
EPSS exploit prediction
EPSS: 0.002 (5.0th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 5th percentile — 5.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: 0.000
Affected products
Weakness classification (CWE)
Public proof-of-concept exploits
References
- kouzili.com/Load-Step.pdf (Third Party Advisory)
- github.com/ARMmbed/mbedtls/releases/ (Third Party Advisory)
- tls.mbed.org/tech-updates/security-advisories/mbedtls-security-advisory-2021-07… (Vendor Advisory)
- af854a3a-2127-422b-91ae-364da2661108
Frequently asked questions
- What is CVE-2021-36647?
- CVE-2021-36647 is a medium-severity vulnerability in Arm Mbed TLS, classified under Use of a Broken or Risky Cryptographic Algorithm. CVSS score: 4.7/10. Published 2023-01-17.
- How severe is CVE-2021-36647?
- Medium severity. CVSS v3 base score is 4.7 out of 10.
- Is CVE-2021-36647 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.