Security readout for executives and security teams
Plain-English summary
CVE-2025-21171 is a high-severity Microsoft .NET remote code execution vulnerability. Microsoft lists affected .NET, Visual Studio 2022, and PowerShell versions. Successful exploitation could let an attacker run code, but the CVSS vector indicates high attack complexity and required user interaction. No active exploitation is indicated in the provided sources.
Executive priority
Treat as a high-priority patching item, especially for developer and build environments. The impact is severe if exploited, but available evidence does not show active exploitation and the attack requires user interaction.
Technical view
The issue is classified as CWE-122, heap-based buffer overflow, with CVSS 3.1 score 7.5. The vector is network-accessible, no privileges required, user interaction required, high complexity, and high impact to confidentiality, integrity, and availability. Microsoft’s advisory is the authoritative remediation source.
Likely exposure
Exposure is most likely where .NET 9.0.0, PowerShell 7.5.0, or Visual Studio 2022 versions 17.6.0, 17.8.0, 17.10.0, or 17.12.0 are installed and unpatched.
Exploitation context
The provided CVSS vector suggests exploitation is not trivial: it requires user interaction and has high attack complexity. The source bundle marks exploit maturity as unproven and does not show CISA KEV listing or active exploitation evidence.
Researcher notes
Public details in the provided bundle are limited to Microsoft’s advisory metadata, CVSS, CWE-122, and affected product versions. Do not assume exploitability details beyond the CVSS vector and vendor advisory. Check MSRC for exact fixed builds.
Mitigation direction
- Review Microsoft’s CVE-2025-21171 advisory for the applicable security update.
- Update affected .NET, PowerShell, and Visual Studio installations per Microsoft guidance.
- Prioritize developer workstations, build servers, and systems processing untrusted content.
- Monitor Microsoft’s advisory for revised affected versions or remediation details.
Validation and detection
- Inventory installed .NET, PowerShell, and Visual Studio versions.
- Compare discovered versions against Microsoft’s affected product list.
- Confirm applicable Microsoft security updates are installed.
- Document systems that cannot be updated and track compensating controls.
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-122: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2025-21171 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 7.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
SSVC decision data
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C1.65.9microsoftVulnerability scoring details
Base CVSS 3.1 score
7.5HighVector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- .NET Remote Code Execution VulnerabilityCVE reference, microsoft · vendor-advisory, patch
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Heap-based Buffer Overflow
Heap-based Buffer Overflow represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.