CVE-2021-3798

Private-key extraction via invalid curve points

Published Aug 23, 2022 · Updated Aug 3, 2024

Improper EC key validation in openCryptoki 3.15.0 through 3.16.0 allows local users to extract Soft-token private keys. The fill_ec_key_from_pubkey() and fill_ec_key_from_privkey() paths accept attacker-controlled EC points without verifying that they lie on the selected curve. A local caller able to invoke C_CreateObject or C_DeriveKey can supply invalid curve data and recover the private key through repeated derivations.

CVSS severity5.5
Medium
EPSS probability0.27%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper EC key validation in openCryptoki 3.15.0 through 3.16.0 allows local users to extract Soft-token private keys. The fill_ec_key_from_pubkey() and fill_ec_key_from_privkey() paths accept attacker-controlled EC points without verifying that they lie on the selected curve. A local caller able to invoke C_CreateObject or C_DeriveKey can supply invalid curve data and recover the private key through repeated derivations.

The record

CVE
CVE-2021-3798
Published
Aug 23, 2022
Updated
Aug 3, 2024
Vendor
openCryptoki
Product
openCryptoki
Classifications
CWE-200, T1552.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 23, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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?

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  1. Affected versionversion=Fixed in v3.17.0

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

openCryptoki · openCryptokiversion=Fixed in v3.17.0

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/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)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-200Exposure of Sensitive Information to an Unauthorized Actor
T1552.004Private Keys

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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