CVE-2023-21100

Local privilege escalation via gzip header overflow

Published Apr 19, 2023 · Updated Feb 5, 2025

Heap buffer overflow in Android 12, 12L, and 13 allows local users to elevate privileges through crafted gzip header data. The inflate routine copies a gzip extra field across repeated calls without limiting the cumulative write to the buffer supplied through inflateGetHeader. Exploitation requires local low-privileged code to process an oversized, fragmented gzip extra field; no user interaction is required.

CVSS severity7.8
High
EPSS probability0.10%
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

Heap buffer overflow in Android 12, 12L, and 13 allows local users to elevate privileges through crafted gzip header data. The inflate routine copies a gzip extra field across repeated calls without limiting the cumulative write to the buffer supplied through inflateGetHeader. Exploitation requires local low-privileged code to process an oversized, fragmented gzip extra field; no user interaction is required.

The record

CVE
CVE-2023-21100
Published
Apr 19, 2023
Updated
Feb 5, 2025
Vendor
Google Cloud
Product
Android
Classifications
CWE-787, T1068
Attack vector
local
Privileges
authenticated

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-12 Android-12L Android-13

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Google Cloud · Androidversion=Android-12 Android-12L Android-13

Published CVSS scores

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

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-787Out-of-bounds Write
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