CVE-2020-4887
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 · uneditedIBM AIX 7.1, 7.2 and AIX VIOS 3.1 could allow a local user to exploit a vulnerability in the gencore user command to create arbitrary files in any directory. IBM X-Force ID: 190911.
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 · moderate confidenceIBM AIX 7.1, 7.2 and AIX VIOS 3.1 contain a vulnerability in the gencore command that allows a local authenticated user to create arbitrary files in any directory on the system, potentially leading to privilege escalation.
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= 3.1= 7.1= 7.2CVSS 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
- None
- Integrity
- High
- Availability
- None
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
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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Identify the AIX or VIOS versionRun 'oslevel -s' on the command line to obtain the full version level of the operating systemAffected if The version begins with 7.1, 7.2 (for AIX) or 3.1 (for VIOS), indicating the system falls within the affected version range
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Verify the gencore command existsExecute 'which gencore' or 'ls -la /usr/bin/gencore' to locate the gencore binary on the systemAffected if The gencore command is found at /usr/bin/gencore or in the PATH, indicating the vulnerable component is present
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Check permissions on the gencore commandRun 'ls -la /usr/bin/gencore' to view the ownership and permission bits of the gencore binaryAffected if Non-privileged users have execute permission (any 'x' in the user/owner column for others or group) which would allow them to invoke the command
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Determine if the vulnerability is still presentCompare the installed AIX/VIOS level against IBM's published patch levels for CVE-2020-4887, or check the gencore binary for known fixed versions using 'lsl -l /usr/bin/gencore' and review IBM's fix documentationAffected if The system is at an affected version level AND no corresponding security patch for CVE-2020-4887 has been applied, leaving the vulnerability unmitigated
A system is affected if it runs AIX 7.1, 7.2 or VIOS 3.1, has the gencore command accessible to local authenticated users, and lacks the specific IBM security patch for CVE-2020-4887.
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.
From vendor dataApply IBM's security patch for CVE-2020-4887 to affected AIX systems and restrict access to the gencore command until the patch is deployed.
- Consultation2.0 h
- Implementation2.0 h
- Testing2.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-4887 — 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-2020-4887 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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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
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