CVE-2020-25082

ECC private-key extraction via signature timing leakage

Published Aug 10, 2021 · Updated Aug 4, 2024

Observable timing discrepancy in Nuvoton NPCT75x firmware 7.2.x before 7.2.2.0 allows physically proximate attackers to extract ECC private keys. The TPM's ECDSA, EC Schnorr, and ECDAA signature operations expose timing differences that permit recovery of the private key. Exploitation requires physical access and repeated measurement of signature timings; the reported consequence is disclosure of the affected ECC key.

CVSS severity3.8
Low
EPSS probability0.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Observable timing discrepancy in Nuvoton NPCT75x firmware 7.2.x before 7.2.2.0 allows physically proximate attackers to extract ECC private keys. The TPM's ECDSA, EC Schnorr, and ECDAA signature operations expose timing differences that permit recovery of the private key. Exploitation requires physical access and repeated measurement of signature timings; the reported consequence is disclosure of the affected ECC key.

The record

CVE
CVE-2020-25082
Published
Aug 10, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-203
Attack vector
physical
Privileges
admin

Timeline

How it unfolded

  1. Aug 10, 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 privilegesadmin

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

1.9NIST NVDAV:L/AC:M/Au:N/C:P/I:N/A:N
3.8MITRECVSS:3.1/AC:H/AV:P/A:N/C:H/I:N/PR:H/S:U/UI: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
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-203Observable Discrepancy

Public exploit references

No public exploit references are available in this record.

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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