CVE-2021-0377

Local defense bypass via conditional patch validation

Published Mar 10, 2021 · Updated Aug 3, 2024

Improper input validation in Android 11 update_engine allows local users to bypass defense-in-depth protections through OTA patch data. DeltaPerformer::Write validated each operation's patch-data hash only when a metadata signature was present, allowing altered data to reach patching libraries. Exploitation requires local control of malicious streaming-update data after manifest verification; user interaction and extra execution privileges are unnecessary.

CVSS severity5.5
Medium
EPSS probability0.12%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper input validation in Android 11 update_engine allows local users to bypass defense-in-depth protections through OTA patch data. DeltaPerformer::Write validated each operation's patch-data hash only when a metadata signature was present, allowing altered data to reach patching libraries. Exploitation requires local control of malicious streaming-update data after manifest verification; user interaction and extra execution privileges are unnecessary.

The record

CVE
CVE-2021-0377
Published
Mar 10, 2021
Updated
Aug 3, 2024
Vendor
Google Cloud
Product
Android
Classifications
CWE-20, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 10, 2021CVE 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=Android-11

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Google Cloud · Androidversion=Android-11

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-20Improper Input Validation
T1068Exploitation for Privilege Escalation

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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