CVE-2021-0303

Local privilege escalation via observer race

Published Jan 11, 2021 · Updated Aug 3, 2024

Android 11 use-after-free in StreamSetObserver allows local users to gain privileges via a race in graph termination handling. The dispatchGraphTerminationMessage() path can notify a destroyed GrpcGraph because StreamSetObserver outlives the graph, causing access to freed memory during concurrent termination processing. User execution privileges are required and no interaction is needed; successful exploitation can elevate privileges, while the public record does not establish a remote attack path.

CVSS severity7.0
High
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

Android 11 use-after-free in StreamSetObserver allows local users to gain privileges via a race in graph termination handling. The dispatchGraphTerminationMessage() path can notify a destroyed GrpcGraph because StreamSetObserver outlives the graph, causing access to freed memory during concurrent termination processing. User execution privileges are required and no interaction is needed; successful exploitation can elevate privileges, while the public record does not establish a remote attack path.

The record

CVE
CVE-2021-0303
Published
Jan 11, 2021
Updated
Aug 3, 2024
Vendor
Google Cloud
Product
Android
Classifications
CWE-362, CWE-416, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 11, 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

7.0NVDCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
6.9NVDAV:L/AC:M/Au:N/C:C/I:C/A:C

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 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-362Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition)
CWE-416Use After Free
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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