CVE-2021-0688

Local privilege escalation via discarded lock request

Published Oct 6, 2021 · Updated Aug 3, 2024

Race condition in Android Framework 8.1 through 11 allows local users to bypass the lock screen through concurrent lock requests. PhoneWindowManager.lockNow queues a ScreenLockTimeout runnable, but updateLockScreenTimeout can clear it before execution, causing the lock request to be ignored. User-level code and no user interaction are required; a successful race leaves the device unlocked and elevates access beyond the caller's privileges.

CVSS severity7.0
High
EPSS probability0.16%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Race condition in Android Framework 8.1 through 11 allows local users to bypass the lock screen through concurrent lock requests. PhoneWindowManager.lockNow queues a ScreenLockTimeout runnable, but updateLockScreenTimeout can clear it before execution, causing the lock request to be ignored. User-level code and no user interaction are required; a successful race leaves the device unlocked and elevates access beyond the caller's privileges.

The record

CVE
CVE-2021-0688
Published
Oct 6, 2021
Updated
Aug 3, 2024
Vendor
Google Cloud
Product
Android
Classifications
CWE-362, T1461, T1404
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 6, 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

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=Android-10 Android-11 Android-8.1 Android-9

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Google Cloud · Androidversion=Android-10 Android-11 Android-8.1 Android-9

Published CVSS scores

7.0NIST NVDCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
4.4NIST NVDAV:L/AC:M/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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-362Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
T1461Lockscreen Bypass
T1404Exploitation for Privilege Escalation

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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo