dbcve.org
AndroidOperating system · Google

CVE-2023-20966

HIGH · 7.8 CVSS v3.1 Published 2023-03-24
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
80/100
Remediation priority · High
Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
In inflate of inflate.c, there is a possible out of bounds write due to a heap buffer overflow. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android-11 Android-12 Android-12L Android-13Android ID: A-242299736

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Heap buffer overflow in the inflate function of zlib's inflate.c allows a local attacker to write beyond allocated heap memory boundaries during decompression operations. This can be leveraged for local privilege escalation without requiring additional execution privileges.

MitigationApply Android security patch levels for March 2023 or later to affected Android versions (11, 12, 12L, 13) which include the patched zlib library; for custom ROMs or embedded Android systems, rebuild with updated zlib sources.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
AndroidOperating system
Affected:= 11.0= 12.0= 12.1= 13.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify Android version
    Navigate to Settings > About Phone (or About Device) > Android version. Alternatively, run `getprop ro.build.version.release` via ADB or terminal.
    Affected if The displayed version is 11.0, 12.0, 12.1, or 13.0. Versions outside this range (10 or lower, 14 or higher) are not affected.
  2. Check security patch level
    Navigate to Settings > About Phone > Security patch level. Alternatively, run `getprop ro.build.version.security_patch` via ADB or terminal.
    Affected if The patch level is earlier than 2023-03-05. If the patch level shows March 2023 or later (2023-03-05 or higher), the vulnerability is patched.
  3. Verify zlib library version (optional)
    If you have ADB access, run `adb shell dumpsys package zlib` or check the libz.so library file version: `adb shell dumpsys meminfo | grep -i zlib`. The library file path is typically /system/lib64/libz.so or /system/lib/libz.so.
    Affected if Unable to verify directly on most devices; the version check is superseded by the patch level check above. If you can extract the library, compare its version to the March 2023 zlib release.

You are affected if your device runs Android 11.0, 12.0, 12.1, or 13.0 AND your security patch level is earlier than March 2023.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply Android security patch levels for March 2023 or later to affected Android versions (11, 12, 12L, 13) which include the patched zlib library; for custom ROMs or embedded Android systems, rebuild with updated zlib sources.

Recommended fix High confidence

March 2023 Android Security Patch Level or later for Android 11, 12, 12L, and 13

  1. 1. Apply the March 2023 Android Security Patch Level (or later) to the affected device
  2. 2. Verify the patch level by going to Settings > About Phone > Android version and checking the Security patch level is March 2023 or later
  3. 3. For devices that no longer receive monthly security updates, consider upgrading to a newer Android version that includes ongoing security support
  4. 4. If immediate patching is not possible, consider restricting device use to trusted environments and avoiding untrusted apps
Caveat Monthly security patches for older devices may eventually cease; some devices may not receive the update due to manufacturer support timelines

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Android Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing8.0 h
  • Review / QA3.0 h
20.0 hours of engineering $3,420
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Scan for this in your stack

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2023-20966 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data