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Fencer Intel
medium 5.3

CVE-2020-36421 json

An issue was discovered in Arm Mbed TLS before 2.23.0

published 5y ago modified 3mo ago also EUVD-2020-23949 , JLSEC-2025-204

cvss
5.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.5%
EPSS 1.5% chance of exploitation in 30 days, percentile 75%
public exploits
0
none known

Summary

An issue was discovered in Arm Mbed TLS before 2.23.0. Because of a side channel in modular exponentiation, an RSA private key used in a secure enclave could be disclosed.

Patch / fix

  • julia MbedTLS_jll 2.16.8+0
  • arm mbed_tls 2.16.7, 2.23.0
  • mbedtls Debian 14, Debian 13, Debian 12 2.16.9-0.1

debian advisories DEBIAN-CVE-2020-36421

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CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
11mo ago

Exploit prediction

1.54% chance of exploitation in the next 30 days, higher than 75% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • github.com https://github.com/ARMmbed/mbedtls/issues/3394 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CISA ADP 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
NVD 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
CNA 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:P/I:N/A:N
OSV 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Affected packages

ecosystem package affected fixed in
julia MbedTLS_jll
<2.16.8+0
2.16.8+0

Classification

Weakness

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.