CVE-2021-38991

Local code execution through undisclosed lscore flaw

Published Jan 11, 2022 · Updated Sep 16, 2024

Local code execution in IBM AIX 7.1 through 7.3 and PowerVM Virtual I/O Server 3.1 allows local users to run code via lscore. IBM identifies lscore as the vulnerable locus but has not published the faulty operation or the form of input that triggers it. Exploitation requires a non-privileged local account; successful execution can compromise system confidentiality, integrity, and availability.

CVSS severity8.4
High
EPSS probability0.27%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Local code execution in IBM AIX 7.1 through 7.3 and PowerVM Virtual I/O Server 3.1 allows local users to run code via lscore. IBM identifies lscore as the vulnerable locus but has not published the faulty operation or the form of input that triggers it. Exploitation requires a non-privileged local account; successful execution can compromise system confidentiality, integrity, and availability.

The record

CVE
CVE-2021-38991
Published
Jan 11, 2022
Updated
Sep 16, 2024
Vendor
IBM
Product
AIX
Classifications
Unavailable
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 11, 2022CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 2024Record 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=7.1
  2. Affected versionversion=7.2
  3. Affected versionversion=7.3

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

IBM · AIXversion=7.1; version=7.2; version=7.3
IBM · PowerVM Virtual I/O Serverversion=3.1

Published CVSS scores

8.4IBM CorporationCVSS:3.0/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
4.6NIST NVDAV:L/AC:L/Au:N/C:P/I:P/A:P

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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

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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