CVE-2021-0308

Local privilege escalation via negative partition index

Published Jan 11, 2021 · Updated Aug 3, 2024

Out-of-bounds write in Android 8.0 through 11 allows physically proximate attackers to gain elevated privileges through crafted media. ReadLogicalParts in basicmbr.cc fails to keep partNum nonnegative when cyclic logical partitions are detected, then uses the underflowed value as a stack-array index. Exploitation requires inserting a maliciously formatted USB or SD card; no user interaction or prior execution privilege is required.

CVSS severity6.8
Medium
EPSS probability0.44%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds write in Android 8.0 through 11 allows physically proximate attackers to gain elevated privileges through crafted media. ReadLogicalParts in basicmbr.cc fails to keep partNum nonnegative when cyclic logical partitions are detected, then uses the underflowed value as a stack-array index. Exploitation requires inserting a maliciously formatted USB or SD card; no user interaction or prior execution privilege is required.

The record

CVE
CVE-2021-0308
Published
Jan 11, 2021
Updated
Aug 3, 2024
Vendor
Google Cloud
Product
Android
Classifications
CWE-787, T1200
Attack vector
physical
Privileges
unauthenticated

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-10
  2. Affected versionversion=Android-11
  3. Affected versionversion=Android-8.0
  4. Affected versionversion=Android-8.1
  5. Affected versionversion=Android-9

What conditions does exploitation require?

Attack vectorphysical
Required privilegesunauthenticated

What is affected?

Google Cloud · Androidversion=Android-10; version=Android-11; version=Android-8.0; version=Android-8.1; version=Android-9

Published CVSS scores

6.8NIST NVDCVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.2NIST NVDAV:L/AC:L/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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorphysical
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1200Hardware Additions

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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