CVE-2018-21058

Key-material exposure via AES-GCM T-Table cache leakage

Published Apr 8, 2020 · Updated Aug 5, 2024

Cache side channel in Samsung Keymaster on Android 7.0 and 8.0 allows attackers to observe AES-GCM key-dependent cache activity. The AES-GCM implementation uses lookup T-Tables, leaving secret-dependent memory accesses in processor-cache state instead of using the Cryptography Extension. Exposure is confined to Android 7.0 devices with Exynos 7420 and Android 8.0 devices with Exynos 8890 or 8996 chipsets.

CVSS severity9.8
Critical
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

Cache side channel in Samsung Keymaster on Android 7.0 and 8.0 allows attackers to observe AES-GCM key-dependent cache activity. The AES-GCM implementation uses lookup T-Tables, leaving secret-dependent memory accesses in processor-cache state instead of using the Cryptography Extension. Exposure is confined to Android 7.0 devices with Exynos 7420 and Android 8.0 devices with Exynos 8890 or 8996 chipsets.

The record

CVE
CVE-2018-21058
Published
Apr 8, 2020
Updated
Aug 5, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-327
Attack vector
Unavailable
Privileges
Unavailable

Timeline

How it unfolded

  1. Apr 8, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 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 vectorUnavailable in this record.
Required privilegesUnavailable in this record.

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.5NIST NVDAV:N/AC:L/Au:N/C:P/I:P/A:P

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)
VectorUnavailable
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-327Use of a Broken or Risky Cryptographic Algorithm

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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