CVE-2023-20966

Local privilege escalation via gzip header overflow

Published Mar 24, 2023 · Updated Feb 25, 2025

Heap buffer overflow in Android 11, 12, 12L, and 13 zlib inflate allows local users to escalate privileges through crafted gzip data. The inflate path copies a gzip header extra field across multiple calls without enforcing the buffer size supplied to inflateGetHeader(). A low-privileged local user can trigger the overwrite without user interaction, and successful exploitation grants higher privileges.

CVSS severity7.8
High
EPSS probability0.10%
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 11, 12, 12L, and 13 zlib inflate allows local users to escalate privileges through crafted gzip data. The inflate path copies a gzip header extra field across multiple calls without enforcing the buffer size supplied to inflateGetHeader(). A low-privileged local user can trigger the overwrite without user interaction, and successful exploitation grants higher privileges.

The record

CVE
CVE-2023-20966
Published
Mar 24, 2023
Updated
Feb 25, 2025
Vendor
Google Cloud
Product
Android
Classifications
CWE-787, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 24, 2023CVE publishedPublication date reported by the CVE source.
  2. Feb 25, 2025Record 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 Android-12 Android-12L Android-13

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Google Cloud · Androidversion=Android-11 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 ADP VulnrichmentCVSS: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

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Your stack

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