BlackTreeIndependent security intelligence
← Back to the CVE catalogue
Full vulnerability report · 2021
CVE-2021-36087High confidence

The CIL compiler in SELinux 3.2 has a heap-based buffer over-read in ebitmap_match_any (called indirectly from cil_check_neverallow)

n/a · n/a

3.3LowCVSS 3.1
Recommended action
Within 7 days

Low technical severity with public exploit material referenced by a structured source; prioritise exposed affected systems while verifying vendor guidance.

Patch available
Direct vendor intelligence

Authoritative vendor CSAF and VEX advisories

Structured product status and remediation from the issuing vendor. Product-state explanations are always visible; large lists can be searched or downloaded.

2 current
SSA-202008 · CSAF 2.0 · revision 1 · interimSiemens ProductCERTSSA-202008: Multiple Vulnerabilities in Ruggedcom Rox Before V2.17.0
11 known affected

The vendor explicitly identifies these products as affected by this CVE.

  • RUGGEDCOM ROX MX5000
  • RUGGEDCOM ROX MX5000RE
  • RUGGEDCOM ROX RX1400
  • RUGGEDCOM ROX RX1500
  • RUGGEDCOM ROX RX1501
  • RUGGEDCOM ROX RX1510
  • RUGGEDCOM ROX RX1511
  • RUGGEDCOM ROX RX1512
  • RUGGEDCOM ROX RX1524
  • RUGGEDCOM ROX RX1536
  • RUGGEDCOM ROX RX5000
Summary
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.
Remediation
Update to V2.17.0 or later version
SSA-398330 · CSAF 2.0 · revision 18 · interimSiemens ProductCERTSSA-398330: Vulnerabilities in the additional GNU/Linux subsystem of the SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP >= V3.1.0 and < V3.1.5
5 known affected

The vendor explicitly identifies these products as affected by this CVE.

  • SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0)
  • SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0)
  • SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0)
  • SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0)
  • SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0)
Summary
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.
Remediation
Update to V3.1.5 or later version
Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Select the national-authority views to include. The exact source language is shown on each matched advisory. Your choice is remembered on this device and encoded in the shareable URL.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2021-22720

No EUVD known-exploited evidence

ENISA has published the identifier mapping but no EUVD description has been stored yet.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
Not supplied in the stored EUVD record
Advisory evidence
No linked advisory details stored yet
Recommended actionWithin 7 days

Low technical severity with public exploit material referenced by a structured source; prioritise exposed affected systems while verifying vendor guidance.

Patch available
01

What, why and how

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.

What

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.

Why

The product reads data past the end, or before the beginning, of the intended buffer.

How

An attacker operating through local access may attempt exploitation with low privileges. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

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.

Why

The product reads data past the end, or before the beginning, of the intended buffer.

How

An attacker operating through local access may attempt exploitation with low privileges. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
Reference recorded

A structured CVE source labels at least one public reference as exploit material. BlackTree has not independently validated that it is safe, reliable or weaponised.

Likely attack path
local access → Out-of-bounds Read → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Local
Privileges required
Low: a basic authenticated account is required
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Unchanged: impact remains within the vulnerable component's security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-125 ↗

CWE-125: Out-of-bounds Read. The product reads data past the end, or before the beginning, of the intended buffer.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L

Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.

AVLocalAttack vector: The attacker needs local access to the vulnerable system.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRLowPrivileges required: The attacker needs basic user-level privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CNoneConfidentiality impact: No direct loss is represented by this metric.INoneIntegrity impact: No direct loss is represented by this metric.ALowAvailability impact: A successful attack can cause a limited loss.
Post-exploitation / living off the land
The issue can support a local privilege or sandbox boundary transition; normal system utilities may then be available in the gained context.
CWE-125Public exploit reference
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

BSI · German · WID-SEC-W-2022-0571Red Hat Enterprise Linux: Mehrere Schwachstellen

Ein entfernter, anonymer, authentisierter oder lokaler Angreifer kann mehrere Schwachstellen in Red Hat Enterprise Linux ausnutzen, um einen Cross-Site-Scripting-Angriff durchzuführen, vertrauliche Informationen offenzulegen, einen Denial-of-Service-Zustand herbeizuführen, Sicherheitsmaßnahmen zu umgehen, beliebigen Code auszuführen, Dateien zu manipulieren und einen nicht spezifizierten Angriff durchzuführen.

Official advisory
BSI · German · WID-SEC-W-2025-0300NetApp ActiveIQ Unified Manager: Mehrere Schwachstellen ermöglichen Denial of Service

Ein lokaler Angreifer kann mehrere Schwachstellen in NetApp ActiveIQ Unified Manager ausnutzen, um einen Denial of Service Angriff durchzuführen.

Official advisory
CERT-FR · French · CERTFR-2023-AVI-1015Multiples vulnérabilités dans les produits Siemens

/CVERecord?id=CVE-2021-3518 Référence CVE CVE-2021-3520 https://www.cve.org/CVERecord?id=CVE-2021-3520 Référence CVE CVE-2021-3537 https://www.cve.org/CVERecord?id=CVE-2021-3537 Référence CVE CVE-2021-3541 https://www.cve.org/CVERecord?id=CVE-2021-3541 Référence CVE CVE-2021-3580 https://www.cve.org/CVERecord?id=CVE-2021-3580 Référence CVE CVE-2021-35942 https://www.cve.org/CVERecord?id=CVE-2021-35942 Référence CVE CVE-2021-36084 https://www.cve.org/CVERecord?id=CVE-2021-36084 Référence CVE CVE-2021-36085 https://www.cve.org/CVERecord?id=CVE-2021-36085 Référence CVE CVE-2021-36086 https://www.cve.org/CVERecord?id=CVE-2021-36086 Référence CVE CVE-2021-36087 https://www.cve.org/CVERecord?id=CVE-2021-36087 Référence CVE CVE-2021-36222 https://www.cve.org/CVERecord?id=CVE-2021-36222 Référence CVE CVE-2021-36690 https://www.cve.org/CVERecord?id=CVE-2021-36690 Référence CVE CVE-2021-3733 https://www.cve.org/CVERecord?id=CVE-2021-3733 Référence CVE CVE-2021-3737 https://www.cve.org/CVERecord?id=CVE-2021-3737 Référence CVE CVE-2021-37600 https://www.cve.org/CVERecord?id=CVE-2021-37600 Référence CVE CVE-2021-37750 https://www.cve.org/CVERecord?id=CVE-2021-37750 Référence CVE CVE-2021-3826 https://www.cve.org/CVERecord?id=CVE-2021-3826 Référence CVE CVE-2021-38604 https://www.cve.org/CVERecord?id=CVE-20

Official advisory
CERT-FR · French · CERTFR-2022-AVI-386Multiples vulnérabilités dans IBM QRadar SIEM

ord?id=CVE-2021-35564 Référence CVE CVE-2021-35565 https://www.cve.org/CVERecord?id=CVE-2021-35565 Référence CVE CVE-2021-35578 https://www.cve.org/CVERecord?id=CVE-2021-35578 Référence CVE CVE-2021-35586 https://www.cve.org/CVERecord?id=CVE-2021-35586 Référence CVE CVE-2021-35588 https://www.cve.org/CVERecord?id=CVE-2021-35588 Référence CVE CVE-2021-3580 https://www.cve.org/CVERecord?id=CVE-2021-3580 Référence CVE CVE-2021-36084 https://www.cve.org/CVERecord?id=CVE-2021-36084 Référence CVE CVE-2021-36085 https://www.cve.org/CVERecord?id=CVE-2021-36085 Référence CVE CVE-2021-36086 https://www.cve.org/CVERecord?id=CVE-2021-36086 Référence CVE CVE-2021-36087 https://www.cve.org/CVERecord?id=CVE-2021-36087 Référence CVE CVE-2021-38869 https://www.cve.org/CVERecord?id=CVE-2021-38869 Référence CVE CVE-2021-38874 https://www.cve.org/CVERecord?id=CVE-2021-38874 Référence CVE CVE-2021-38878 https://www.cve.org/CVERecord?id=CVE-2021-38878 Référence CVE CVE-2021-38919 https://www.cve.org/CVERecord?id=CVE-2021-38919 Référence CVE CVE-2021-38939 https://www.cve.org/CVERecord?id=CVE-2021-38939 Référence CVE CVE-2021-41035 https://www.cve.org/CVERecord?id=CVE-2021-41035 Référence CVE CVE-2021-41182 https://www.cve.org/CVERecord?id=CVE-2021-41182 Référence CVE CVE-2021-41183 https://www.cve.org/CVERecord?id=

Official advisory
NCSC-NL · Dutch · NCSC-2025-0382Kwetsbaarheden verholpen in Siemens producten

Red Hat Enterprise Linux and SELinux 3.2 have multiple vulnerabilities, including denial of service and arbitrary code execution risks, affecting various components and requiring user interaction or elevated privileges for exploitation.

Official advisory
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Patch available
Affected
RUGGEDCOM ROX MX5000; RUGGEDCOM ROX MX5000RE; RUGGEDCOM ROX RX1400; RUGGEDCOM ROX RX1500; RUGGEDCOM ROX RX1501; RUGGEDCOM ROX RX1510; RUGGEDCOM ROX RX1511; RUGGEDCOM ROX RX1512; RUGGEDCOM ROX RX1524; RUGGEDCOM ROX RX1536; RUGGEDCOM ROX RX5000
Fixed
An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
Action
Update to V2.17.0 or later version
Workaround
No verified workaround is recorded. Limit untrusted access and use least privilege until authoritative guidance is available.
04

Evidence and provenance

Published 1 Jul 2021 · Last source change 3 Nov 2025, 21:44 UTC · CWE-125 · Out-of-bounds Read

CVE recordCVE.org · 5.2
CVSS sourceNIST NVD
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2021-22720
Product sourceVendor CSAF · Siemens ProductCERT
Remediation sourceVendor CSAF · Siemens ProductCERT
CWE sourceNIST NVD
NVD statusNVD modified after enrichment

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates →

No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.

Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Fixed release or patch reference recorded
ENISA EUVD · EUVD-2021-22720↗Vendor CSAF · Siemens ProductCERT↗Public exploit reference↗Patch or update reference↗CVE authority or vendor reference↗Official CVE record (CNA and ADP data)↗NVD record↗
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2021-36087 · cve.blacktree.nl