CVE-2023-21084

Privilege escalation via SHA-1 AVB hashtrees

Published Apr 19, 2023 · Updated Feb 5, 2025

Improper cryptographic verification in Android 13 allows local users with System privileges to escalate privileges without interaction. In buildPropFile in filesystem.go, the Soong image rule leaves the AVB hashtree algorithm unset, causing avbtool to default to SHA-1 for Microdroid system and vendor images. Exploitation requires existing System execution privileges and affects privilege boundaries backed by those verified images; no remote path is reported.

CVSS severity6.7
Medium
EPSS probability0.09%
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

Improper cryptographic verification in Android 13 allows local users with System privileges to escalate privileges without interaction. In buildPropFile in filesystem.go, the Soong image rule leaves the AVB hashtree algorithm unset, causing avbtool to default to SHA-1 for Microdroid system and vendor images. Exploitation requires existing System execution privileges and affects privilege boundaries backed by those verified images; no remote path is reported.

The record

CVE
CVE-2023-21084
Published
Apr 19, 2023
Updated
Feb 5, 2025
Vendor
Google Cloud
Product
Android
Classifications
T1068
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Apr 19, 2023CVE publishedPublication date reported by the CVE source.
  2. Feb 5, 2025Record 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-13

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

Google Cloud · Androidversion=Android-13

Published CVSS scores

6.7CISA-ADPCVSS:3.1/AV:L/AC:L/PR:H/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.

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
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1068Exploitation 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