CVE-2021-20491

Server crash via command-parameter bounds failure

Published Apr 16, 2021 · Updated Sep 16, 2024

Stack-based buffer overflow in IBM Spectrum Protect Server 7.1 and 8.1 allows local users with administrator access to crash the server. The command parser fails to enforce bounds on an improper command parameter, overflowing a stack buffer. Administrative command access is required, and successful exploitation interrupts service without reported data disclosure or modification.

CVSS severity4.4
Medium
EPSS probability0.26%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stack-based buffer overflow in IBM Spectrum Protect Server 7.1 and 8.1 allows local users with administrator access to crash the server. The command parser fails to enforce bounds on an improper command parameter, overflowing a stack buffer. Administrative command access is required, and successful exploitation interrupts service without reported data disclosure or modification.

The record

CVE
CVE-2021-20491
Published
Apr 16, 2021
Updated
Sep 16, 2024
Vendor
IBM
Product
IBM Storage Protect Server
Classifications
CWE-787, T1499
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Apr 16, 2021CVE 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=8.1

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

IBM · IBM Storage Protect Serverversion=7.1; version=8.1

Published CVSS scores

4.4NIST National Vulnerability DatabaseCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
4.4IBMCVSS:3.0/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/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.

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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
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1499Endpoint Denial of Service

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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