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Full vulnerability report · 2021
CVE-2021-42373High confidence

A NULL pointer dereference in Busybox's man applet leads to denial of service when a section name is supplied but no page argument is given

busybox · busybox

5.5MediumCVSS 3.1
Recommended action
Scheduled

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

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.

3 current
SSA-831302 · CSAF 2.0 · revision 5 · interimSiemens ProductCERTSSA-831302: Vulnerabilities in the BIOS of the SIMATIC S7-1500 TM MFP before V1.3.0
1 known affected

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

  • SIMATIC S7-1500 TM MFP - BIOS
Summary
A NULL pointer dereference in Busybox's man applet leads to denial of service when a section name is supplied but no page argument is given.
Remediation
Update to V1.3.0 or later version
SSA-419740 · CSAF 2.0 · revision 1 · finalSiemens ProductCERTSSA-419740: Multiple Third-Party Component Vulnerabilities in RUGGEDCOM and SCALANCE Products before V7.2
20 known affected

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

  • RUGGEDCOM RM1224 LTE(4G) EU (6GK6108-4AM00-2BA2)
  • RUGGEDCOM RM1224 LTE(4G) NAM (6GK6108-4AM00-2DA2)
  • SCALANCE M804PB (6GK5804-0AP00-2AA2)
  • SCALANCE M812-1 ADSL-Router (Annex A) (6GK5812-1AA00-2AA2)
  • SCALANCE M812-1 ADSL-Router (Annex B) (6GK5812-1BA00-2AA2)
  • SCALANCE M816-1 ADSL-Router (Annex A) (6GK5816-1AA00-2AA2)
  • SCALANCE M816-1 ADSL-Router (Annex B) (6GK5816-1BA00-2AA2)
  • SCALANCE M826-2 SHDSL-Router (6GK5826-2AB00-2AB2)
  • SCALANCE M874-2 (6GK5874-2AA00-2AA2)
  • SCALANCE M874-3 (6GK5874-3AA00-2AA2)
  • SCALANCE M876-3 (EVDO) (6GK5876-3AA02-2BA2)
  • SCALANCE M876-3 (ROK) (6GK5876-3AA02-2EA2)
Summary
A NULL pointer dereference in Busybox's man applet leads to denial of service when a section name is supplied but no page argument is given.
Remediation
Update to V7.2 or later version
SSA-565386 · CSAF 2.0 · revision 1 · interimSiemens ProductCERTSSA-565386: Third-Party Component Vulnerabilities in SCALANCE W-700 IEEE 802.11ax devices before V2.0
9 known affected

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

  • SCALANCE WAM763-1 (6GK5763-1AL00-7DA0)
  • SCALANCE WAM766-1 (EU) (6GK5766-1GE00-7DA0)
  • SCALANCE WAM766-1 (US) (6GK5766-1GE00-7DB0)
  • SCALANCE WAM766-1 EEC (EU) (6GK5766-1GE00-7TA0)
  • SCALANCE WAM766-1 EEC (US) (6GK5766-1GE00-7TB0)
  • SCALANCE WUM763-1 (6GK5763-1AL00-3AA0)
  • SCALANCE WUM763-1 (6GK5763-1AL00-3DA0)
  • SCALANCE WUM766-1 (EU) (6GK5766-1GE00-3DA0)
  • SCALANCE WUM766-1 (US) (6GK5766-1GE00-3DB0)
Summary
A NULL pointer dereference in Busybox's man applet leads to denial of service when a section name is supplied but no page argument is given.
Remediation
Update to V2.0 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-2021-29344

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 actionScheduled

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

Patch available
01

What, why and how

A NULL pointer dereference in Busybox's man applet leads to denial of service when a section name is supplied but no page argument is given

What

A NULL pointer dereference in Busybox's man applet leads to denial of service when a section name is supplied but no page argument is given

Why

The product dereferences a pointer that it expects to be valid but is NULL.

How

An attacker operating through local access may attempt exploitation with low privileges. If successful, the issue may disrupt the affected service.

What

A NULL pointer dereference in Busybox's man applet leads to denial of service when a section name is supplied but no page argument is given

Why

The product dereferences a pointer that it expects to be valid but is NULL.

How

An attacker operating through local access may attempt exploitation with low privileges. If successful, the issue may disrupt the affected service.

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.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
local access → NULL Pointer Dereference → disrupt the affected service
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-476 ↗

CWE-476: NULL Pointer Dereference. The product dereferences a pointer that it expects to be valid but is NULL.

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:H

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.AHighAvailability impact: A successful attack can cause a major 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.
Denial of serviceCWE-476
A

Official authority intelligence

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

BSI · German · WID-SEC-2023-1432Siemens SIMATIC S7: Mehrere Schwachstellen

Ein Angreifer aus dem angrenzenden Netzwerk oder ein entfernter, anonymer, authentisierter, physischer oder lokaler Angreifer kann mehrere Schwachstellen in Siemens SIMATIC S7 ausnutzen, um beliebigen Code auszuführen, Sicherheitsmaßnahmen zu umgehen, vertrauliche Informationen offenzulegen, einen Denial-of-Service-Zustand herbeizuführen, seine Privilegien zu erweitern und Daten zu manipulieren.

Official advisory ↗
BSI · German · WID-SEC-2022-2028BusyBox: Mehrere Schwachstellen

Ein entfernter, anonymer oder authentisierter Angreifer kann mehrere Schwachstellen in BusyBox ausnutzen, um einen Denial of Service Angriff durchzuführen, Informationen offenzulegen oder beliebigen Code auszuführen.

Official advisory ↗
Cyber Security Agency of Singapore · English · CSA-SB-20211117Security Bulletin 17 Nov 2021

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 17 Nov 2021, published on 17 November 2021. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
CERT-FR · French · CERTFR-2025-AVI-0158Multiples vulnérabilités dans les produits NetApp

in de sécurité NetApp NTAP-20211223-0002 du 23 décembre 2021 https://security.netapp.com/advisory/ntap-20211223-0002/ Bulletin de sécurité NetApp NTAP-20230316-0011 du 16 mars 2023 https://security.netapp.com/advisory/ntap-20230316-0011/ Bulletin de sécurité NetApp NTAP-20230706-0008 du 06 juillet 2023 https://security.netapp.com/advisory/ntap-20230706-0008/ Bulletin de sécurité NetApp NTAP-20240415-0013 du 15 avril 2024 https://security.netapp.com/advisory/ntap-20240415-0013/ Référence CVE CVE-2020-16593 https://www.cve.org/CVERecord?id=CVE-2020-16593 Référence CVE CVE-2020-16599 https://www.cve.org/CVERecord?id=CVE-2020-16599 Référence CVE CVE-2021-42373 https://www.cve.org/CVERecord?id=CVE-2021-42373 Référence CVE CVE-2021-42374 https://www.cve.org/CVERecord?id=CVE-2021-42374 Référence CVE CVE-2021-42375 https://www.cve.org/CVERecord?id=CVE-2021-42375 Référence CVE CVE-2021-42376 https://www.cve.org/CVERecord?id=CVE-2021-42376 Référence CVE CVE-2021-42377 https://www.cve.org/CVERecord?id=CVE-2021-42377 Référence CVE CVE-2021-42378 https://www.cve.org/CVERecord?id=CVE-2021-42378 Référence CVE CVE-2021-42379 https://www.cve.org/CVERecord?id=CVE-2021-42379 Référence CVE CVE-2021-42380 https://www.cve.org/CVERecord?id=CVE-2021-42380 Référence CVE CVE-2021-42381 https://www.cve.org/CVERecord?id=

Official advisory ↗
CERT-FR · French · CERTFR-2023-AVI-0453Multiples vulnérabilités dans les produits Siemens

/CVERecord?id=CVE-2021-3326 Référence CVE CVE-2021-33574 https://www.cve.org/CVERecord?id=CVE-2021-33574 Référence CVE CVE-2021-33655 https://www.cve.org/CVERecord?id=CVE-2021-33655 Référence CVE CVE-2021-35942 https://www.cve.org/CVERecord?id=CVE-2021-35942 Référence CVE CVE-2021-3759 https://www.cve.org/CVERecord?id=CVE-2021-3759 Référence CVE CVE-2021-38604 https://www.cve.org/CVERecord?id=CVE-2021-38604 Référence CVE CVE-2021-3998 https://www.cve.org/CVERecord?id=CVE-2021-3998 Référence CVE CVE-2021-3999 https://www.cve.org/CVERecord?id=CVE-2021-3999 Référence CVE CVE-2021-4037 https://www.cve.org/CVERecord?id=CVE-2021-4037 Référence CVE CVE-2021-42373 https://www.cve.org/CVERecord?id=CVE-2021-42373 Référence CVE CVE-2021-42374 https://www.cve.org/CVERecord?id=CVE-2021-42374 Référence CVE CVE-2021-42375 https://www.cve.org/CVERecord?id=CVE-2021-42375 Référence CVE CVE-2021-42376 https://www.cve.org/CVERecord?id=CVE-2021-42376 Référence CVE CVE-2021-42377 https://www.cve.org/CVERecord?id=CVE-2021-42377 Référence CVE CVE-2021-42378 https://www.cve.org/CVERecord?id=CVE-2021-42378 Référence CVE CVE-2021-42379 https://www.cve.org/CVERecord?id=CVE-2021-42379 Référence CVE CVE-2021-42380 https://www.cve.org/CVERecord?id=CVE-2021-42380 Référence CVE CVE-2021-42381 https://www.cve.org/CVERecord?id=

Official advisory ↗
CERT-FR · French · CERTFR-2023-AVI-0220Multiples vulnérabilités dans les produits Siemens

rg/CVERecord?id=CVE-2017-5715 Référence CVE CVE-2018-12886 https://www.cve.org/CVERecord?id=CVE-2018-12886 Référence CVE CVE-2018-25032 https://www.cve.org/CVERecord?id=CVE-2018-25032 Référence CVE CVE-2019-1071 https://www.cve.org/CVERecord?id=CVE-2019-1071 Référence CVE CVE-2019-1073 https://www.cve.org/CVERecord?id=CVE-2019-1073 Référence CVE CVE-2019-1125 https://www.cve.org/CVERecord?id=CVE-2019-1125 Référence CVE CVE-2021-26401 https://www.cve.org/CVERecord?id=CVE-2021-26401 Référence CVE CVE-2021-4034 https://www.cve.org/CVERecord?id=CVE-2021-4034 Référence CVE CVE-2021-4149 https://www.cve.org/CVERecord?id=CVE-2021-4149 Référence CVE CVE-2021-42373 https://www.cve.org/CVERecord?id=CVE-2021-42373 Référence CVE CVE-2021-42374 https://www.cve.org/CVERecord?id=CVE-2021-42374 Référence CVE CVE-2021-42375 https://www.cve.org/CVERecord?id=CVE-2021-42375 Référence CVE CVE-2021-42376 https://www.cve.org/CVERecord?id=CVE-2021-42376 Référence CVE CVE-2021-42377 https://www.cve.org/CVERecord?id=CVE-2021-42377 Référence CVE CVE-2021-42378 https://www.cve.org/CVERecord?id=CVE-2021-42378 Référence CVE CVE-2021-42379 https://www.cve.org/CVERecord?id=CVE-2021-42379 Référence CVE CVE-2021-42380 https://www.cve.org/CVERecord?id=CVE-2021-42380 Référence CVE CVE-2021-42381 https://www.cve.org/CVERecord?id=

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2021-015216Busybox における NULL ポインタデリファレンスに関する脆弱性

Busybox には、 NULL ポインタデリファレンスに関する脆弱性が存在します。

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
SIMATIC S7-1500 TM MFP - BIOS
Fixed
No fixed version is explicitly recorded in the structured CVE data.
Action
Update to V1.3.0 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 15 Nov 2021 · Last source change 4 Aug 2024, 03:30 UTC · CWE-476 · NULL Pointer Dereference

CVE recordCVE.org · 5.1
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-2021-29344
Product sourceVendor CSAF · Siemens ProductCERT
Remediation sourceVendor CSAF · Siemens ProductCERT
CWE sourceCNA
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
ENISA EUVD · EUVD-2021-29344↗Vendor CSAF · Siemens ProductCERT↗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-2021-42373 · cve.blacktree.nl