CVE-2021-36647

mediumpriority · track · 19OT risk · elevatedEPSS 0.002 · 6 %ileEURUUS

grimoire priorityP3 · Track

Exploitable?

—

no known exploitation

Likely / severe?

0.16% (6th) EPSS

CVSS 4.7 · medium

Is it mine?

7 products

Check your exposure

Who says so?

4 sources

cnnvd · enisa_euvd · fstec_bdu · nvd

EPSS · scored 2026-10-27

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.

cvss

Technical severity, 0–10. One row per scoring source.

4.7

010

base score 0–10 · higher = more severe · hover a vector to decode

v3.14.7mediumCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:Nprimary · NVD / NIST USexploitability 1 · impact 3.6

v3.14.7mediumAV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:Nsecondary · FSTEC (BDU) RU

v3.14.7mediumCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:Nsecondary · ENISA EU

v3.14.7mediumCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:Nsecondaryexploitability 1 · impact 3.6

v3.14.3mediumCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N/E:Usecondary · CVSS-BT (t0sche)

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Trackcoordinatorcisa_ssvcUS

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-327USprimaryCWE-327US

affected products (7)

Products and version ranges known to be affected.

n/a n/a≤ n/aenisa_euvdEU
ARM Limited Mbed TLS≤ 2.16.11fstec_bduRU
ARM Limited Mbed TLS≥ 2.17.0 до 2.27.0fstec_bduRU
ARM Limited Mbed TLS2.28.0 → 3.0.0fstec_bduRU
arm mbed tls< 2.16.11nvdUScpe:2.3:a:arm:mbed_tls:*:*:*:*:*:*:*:*
arm mbed tls2.17.0 → 2.27.0nvdUScpe:2.3:a:arm:mbed_tls:*:*:*:*:*:*:*:*
trustedfirmware mbed tls2.28.0 → 3.0.0nvdUScpe:2.3:a:trustedfirmware:mbed_tls:*:*:*:*:*:*:*:*

also known as (4)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd fstec_bdu nvd NVD CVE.org MITRE

published 2023-01-17modified 2026-06-17

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+913 more

references (12)

External citations — patches, advisories, analysis.

scry

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