What is the CVSS score of CVE-2021-20491?

CVE-2021-20491 has a CVSS 3.1 base score of 4.4 (Medium). CVSS vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H. EPSS exploitation probability: 0.3%.

Is there a patch available for CVE-2021-20491?

Yes, a patch is available for CVE-2021-20491. Update the affected software to the latest version immediately.

Spectrum Protect CVE-2021-20491

MEDIUM

Out-of-bounds Write (CWE-787)

2021-04-16 psirt@us.ibm.com

Buffer Overflow Memory Corruption IBM Spectrum Protect

4.4

CVSS 3.1 · NVD

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Vulnerability Assessment

Weakness	CWE CWE-787 ASVS 5.0 V15 - Secure Coding and Architecture Bounds checking, write limits MITRE ATT&CK 2 techniques across 2 tactics: Execution, Privilege Escalation The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. Sign in to read
Impact	CVSS score of 4.4 (MEDIUM). Attack characteristics: local attack vector, low complexity, high privileges required, no user interaction not required.
Exploit ScenarioDerived	A local attacker with access to the system could write data beyond allocated buffer boundaries leading to code execution or crashes.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).

Patch available 0.3% exploitation probability (EPSS)

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AnalysisAI

IBM Spectrum Protect Server 7.1 and 8.1 is subject to a stack-based buffer overflow caused by improper bounds checking during the parsing of commands. Rated medium severity (CVSS 4.4), this vulnerability is low attack complexity. This Out-of-bounds Write vulnerability could allow attackers to write data beyond allocated buffer boundaries leading to code execution or crashes.

RemediationAI

A vendor patch is available. Apply the latest security update as soon as possible. Validate write boundaries, use memory-safe languages, enable compiler protections (ASLR, stack canaries).

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

This vulnerability is classified as Out-of-bounds Write (CWE-787), which allows attackers to write data beyond allocated buffer boundaries leading to code execution or crashes. IBM Spectrum Protect Server 7.1 and 8.1 is subject to a stack-based buffer overflow caused by improper bounds checking during the parsing of commands. By issuing such a command with an improper parameter, an authorized administrator could overflow a buffer and cause the server to crash. IBM X-Force ID: 197792. Affected products include: Ibm Spectrum Protect.

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 4.4 MEDIUM

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

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector

Local

Attack Complexity

Low

Privileges Required

High

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

DescriptionNVD

IBM Spectrum Protect Server 7.1 and 8.1 is subject to a stack-based buffer overflow caused by improper bounds checking during the parsing of commands. By issuing such a command with an improper parameter, an authorized administrator could overflow a buffer and cause the server to crash. IBM X-Force ID: 197792.

Threat Intelligence Overview

EPSS Score

0.3%

Top 83% exploitable

Data Quality

2 sources

Confidence: Low

NVD

CVE.org

EPSS

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue

Severity MEDIUM

CISA KEV No

Public POC No

EPSS 0.3%

Patch available Yes

Active threat No

Deciding rule

MEDIUM severity (CVSS 4.0-6.9)

What every action level means

Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.

Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.

This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.

This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.

Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived

Defer

Exploitation· derived

None

System Exposure· derived

Small

Automatable· derived

Human Impact· derived

Medium

Priority Score

Low Medium High Critical

KEV: 0

EPSS: 0

CVSS: +22

PoC: 0

Weaponized: 0

Threat intel: 0

Gov advisory: 0

Attack Technique

Buffer Overflow HIGH

A buffer overflow occurs when a program writes more data to a memory buffer than it was allocated to hold, causing the excess data to spill into adjacent memory regions.

Memory Corruption HIGH

Memory corruption occurs when a program writes data beyond the boundaries of allocated memory regions or accesses memory in unintended ways, violating the integrity of the process's address space.