CVE-2020-27209Public exploit

Private-key extraction via unrandomized elliptic-curve Z coordinate

Published May 20, 2021 · Updated Aug 4, 2024

Side-channel exposure in micro-ecc 1.0 allows physically proximate attackers to extract private ECC keys during ECDSA signing. The uECC_sign_with_k operation passes a null initial_Z into EccPoint_mult, fixing the projective Z coordinate instead of randomizing it and causing secret-dependent scalar multiplication steps to produce distinguishable power traces. Physical access to measure device power during signing is required; successful extraction compromises signature-key confidentiality only.

CVSS severity7.5
High
EPSS probability1.54%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Side-channel exposure in micro-ecc 1.0 allows physically proximate attackers to extract private ECC keys during ECDSA signing. The uECC_sign_with_k operation passes a null initial_Z into EccPoint_mult, fixing the projective Z coordinate instead of randomizing it and causing secret-dependent scalar multiplication steps to produce distinguishable power traces. Physical access to measure device power during signing is required; successful extraction compromises signature-key confidentiality only.

The record

CVE
CVE-2020-27209
Published
May 20, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
Unavailable
Attack vector
physical
Privileges
Unavailable

Timeline

How it unfolded

  1. May 20, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorphysical
Required privilegesUnavailable in this record.

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
5.0NIST NVDAV:N/AC:L/Au:N/C:P/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorphysical
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

No sourced classifications are available.

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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