CVE-2021-0519

Local information disclosure via unchecked bitstream flush

Published Aug 17, 2021 · Updated Aug 3, 2024

Heap buffer overflow in Android 8.1 through 11 allows local users to disclose information through the H.264 encoder without interaction. BITSTREAM_FLUSH in ih264e_bitstream.h can write past the heap output buffer because emulation-prevention insertion lacks an overflow check. A malicious application needs no additional execution privileges or user interaction; public records do not identify the specific information exposed.

CVSS severity7.8
High
EPSS probability0.24%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap buffer overflow in Android 8.1 through 11 allows local users to disclose information through the H.264 encoder without interaction. BITSTREAM_FLUSH in ih264e_bitstream.h can write past the heap output buffer because emulation-prevention insertion lacks an overflow check. A malicious application needs no additional execution privileges or user interaction; public records do not identify the specific information exposed.

The record

CVE
CVE-2021-0519
Published
Aug 17, 2021
Updated
Aug 3, 2024
Vendor
Google Cloud
Product
Android
Classifications
CWE-787
Attack vector
local
Privileges
Unavailable

Timeline

How it unfolded

  1. Aug 17, 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-10 Android-11 Android-8.1 Android-9

What conditions does exploitation require?

Attack vectorlocal
Required privilegesUnavailable in this record.

What is affected?

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

Published CVSS scores

7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

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)
Vectorlocal
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write

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

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Your stack

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