CVE-2021-1048
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 · uneditedIn ep_loop_check_proc of eventpoll.c, there is a possible way to corrupt memory due to a use after free. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android kernelAndroid ID: A-204573007References: Upstream kernel
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 confidenceA use-after-free vulnerability exists in the ep_loop_check_proc function of eventpoll.c in the Android kernel. The vulnerability allows corruption of memory due to improper handling of the epoll data structures, potentially enabling a local attacker to escalate privileges to root without requiring additional execution privileges.
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 dataall versionsCVSS 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 checksWork through these to decide whether this CVE applies to you.
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Check Android versionGo to Settings > About Phone > Android version or run 'getprop ro.build.version.release' via ADBAffected if The device runs any version of Android that has not received the CVE-2021-1048 patch
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Check kernel versionRun 'uname -r' via ADB shell or check via Settings > About Phone > Kernel versionAffected if The kernel version is older than the patched version containing the CVE-2021-1048 fix in eventpoll.c
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Check Android security patch levelRun 'getprop ro.build.version.security_patch' via ADB or check Settings > About Phone > Android security patch levelAffected if The security patch level is earlier than the month the CVE-2021-1048 patch was released (November 2021)
A device is affected if it runs any Android version whose kernel still contains the unpatched use-after-free vulnerability in the ep_loop_check_proc function of eventpoll.c, typically indicated by a pre-November 2021 security patch level.
Generated from the published advisory. Verify against your own configuration.
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 · scopedApply the upstream kernel patch for CVE-2021-1048 to fix the use-after-free in eventpoll.c. Kernel updates should be deployed through Android's regular security patch cycle.
Android Security Patch Level 2022-01-01 or later (kernel update containing the eventpoll.c fix)
- Apply the Android security update that addresses CVE-2021-1048. This vulnerability was addressed in the Android Security Bulletin released in January 2022.
- Ensure your device is running the January 2022 Android Security Patch Level (2022-01-01) or later.
- Go to Settings > Security > Security update and verify the patch level is current.
- For devices receiving monthly security updates, ensure you have installed all available updates through your device manufacturer or carrier.
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation4.0 h
- Implementation8.0 h
- Testing12.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $7,616.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-1048 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2021-1048 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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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.
- 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
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