CVE-2021-39680

Local heap-data disclosure via uninitialized transform buffer

Published Jan 14, 2022 · Updated Aug 4, 2024

Information disclosure in Google Titan M2 on affected Pixel devices allows local users with System privileges to read heap data. The sec_SHA256_Transform function in sha256_core.c processes uninitialized data, exposing residual heap contents during SHA-256 transformation. Exploitation requires local System execution privileges and no user interaction; the documented consequence is limited to confidentiality.

CVSS severity4.4
Medium
EPSS probability0.11%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Information disclosure in Google Titan M2 on affected Pixel devices allows local users with System privileges to read heap data. The sec_SHA256_Transform function in sha256_core.c processes uninitialized data, exposing residual heap contents during SHA-256 transformation. Exploitation requires local System execution privileges and no user interaction; the documented consequence is limited to confidentiality.

The record

CVE
CVE-2021-39680
Published
Jan 14, 2022
Updated
Aug 4, 2024
Vendor
Google
Product
Titan M2
Classifications
CWE-908, T1005
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Jan 14, 2022CVE 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?

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  1. Affected versionversion=Android kernel

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

Google · Titan M2version=Android kernel

Published CVSS scores

4.4NIST NVDCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N
2.1NIST NVDAV:L/AC:L/Au:N/C:P/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-908Use of Uninitialized Resource
T1005Data from Local System

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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