CVE Program Container

Answer in brief

CVE-2021-4090 records a Unknown severity vulnerability in CVE Program Container. The current sources do not mark it as known exploited. The current feed maps Linux/kernel (generic), Siemens/SIMATIC S7-1500 TM MFP - GNU/Linux subsystem (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Feb 18, 2022Updated Aug 25, 2026Source checked Aug 25, 2026First seen by HOL Aug 25, 2026Material review Aug 25, 2026

Upstream Advisory

Key facts

Risk: Unknown severitySource severity not reported
Exploitation: Not marked as known exploited
Affected software: 2 mapped packages or products
Fix availability: Available

Why this deserves its current priority

A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Linux/kernel (generic), Siemens/SIMATIC S7-1500 TM MFP - GNU/Linux subsystem (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Linux/kernelgeneric	>=5.11 <5.15.5	5.15.5
Siemens/SIMATIC S7-1500 TM MFP - GNU/Linux subsystemgeneric	>=0 <*	*

Recommended response

Check inventory. Check lockfiles and deployed manifests for Linux/kernel, Siemens/SIMATIC S7-1500 TM MFP - GNU/Linux subsystem.
Review the reported fix. Update Linux/kernel to 5.15.5; Siemens/SIMATIC S7-1500 TM MFP - GNU/Linux subsystem to * if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Feb 18, 2022
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Aug 25, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Aug 25, 2026

Sources and claim methodology

Upstream source description

An out-of-bounds (OOB) memory write flaw was found in the NFSD in the Linux kernel. Missing sanity may lead to a write beyond bmval[bmlen-1] in nfsd4_decode_bitmap4 in fs/nfsd/nfs4xdr.c. In this flaw, a local attacker with user privilege may gain access to out-of-bounds memory, leading to a system integrity and confidentiality threat.

Quoted source text, attributed separately from HOL analysis.