What is the CVSS score of CVE-2021-36087?

CVE-2021-36087 has a CVSS 3.1 base score of 3.3 (Low). CVSS vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L. EPSS exploitation probability: 0.5%.

Is there a public PoC exploit available for CVE-2021-36087?

Yes, a public proof-of-concept exploit is available for CVE-2021-36087. Prioritise patching immediately. EPSS: 0.5%.

Is there a patch available for CVE-2021-36087?

Yes, a patch is available for CVE-2021-36087. Update the affected software to the latest version immediately.

Selinux CVE-2021-36087

LOW

Out-of-bounds Read (CWE-125)

2021-07-01 cve@mitre.org

Buffer Overflow Information Disclosure Fedora Selinux Fedoraproject Selinux Project

3.3

CVSS 3.1 · NVD

View

Vulnerability Assessment

Weakness	CWE CWE-125 ASVS 5.0 V15 - Secure Coding and Architecture Bounds checking, read limits MITRE ATT&CK 1 technique across 1 tactic: Collection 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 3.3 (LOW). Attack characteristics: local attack vector, low complexity, low privileges required, no user interaction not required. Public proof-of-concept exploit code is available.
Exploit ScenarioDerived	A local attacker with access to the system could read data from memory outside the intended buffer boundaries.

Monitor Track and reassess. Why: LOW severity (CVSS 0.1-3.9).

Patch available 0.5% exploitation probability (EPSS)

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AnalysisAI

The CIL compiler in SELinux 3.2 has a heap-based buffer over-read in ebitmap_match_any (called indirectly from cil_check_neverallow). Rated low severity (CVSS 3.3), this vulnerability is low attack complexity. Public exploit code available.

RemediationAI

A vendor patch is available. Apply the latest security update as soon as possible. Validate array indices and buffer lengths. Use memory-safe languages. Enable AddressSanitizer during testing.

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 Read (CWE-125), which allows attackers to read data from memory outside the intended buffer boundaries. The CIL compiler in SELinux 3.2 has a heap-based buffer over-read in ebitmap_match_any (called indirectly from cil_check_neverallow). This occurs because there is sometimes a lack of checks for invalid statements in an optional block. Affected products include: Selinux Project Selinux, Fedoraproject Fedora.

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 3.3 LOW

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

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

Low

DescriptionNVD

The CIL compiler in SELinux 3.2 has a heap-based buffer over-read in ebitmap_match_any (called indirectly from cil_check_neverallow). This occurs because there is sometimes a lack of checks for invalid statements in an optional block.

Threat Intelligence Overview

EPSS Score

0.5%

Top 64% exploitable

Exploit

POC

Public exploit code exists

Data Quality

4 sources

Confidence: Medium

NVD

CVE.org

EPSS

GitHub

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 LOW

CISA KEV No

Public POC Yes

EPSS 0.5%

Patch available Yes

Active threat No

Deciding rule

LOW severity (CVSS 0.1-3.9)

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

Poc

System Exposure· derived

Small

Automatable· derived

Human Impact· derived

Low

Priority Score

Low Medium High Critical

KEV: 0

EPSS: 0

CVSS: +16

PoC: +20

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.

Information Disclosure MEDIUM

Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.