Security readout for executives and security teams
Plain-English summary
A network attacker could trick a user on an affected Windows system into exposing an NTLM credential hash through a manipulated file name or path. The issue can compromise credential confidentiality but does not directly alter data or disrupt services. User interaction is required.
Executive priority
Treat as a normal but timely patching priority, accelerated for legacy servers, high-value accounts, and systems exposed to untrusted content. It is not supported as an emergency active-exploitation event, but credential-hash disclosure can enable broader account compromise if other defenses are weak.
Technical view
CVE-2026-20925 is a CWE-73 external path-control flaw in Windows NTLM. It is remotely reachable without prior privileges, requires user interaction, and may disclose NTLM hashes. CVSS 3.1 is 6.5, with high confidentiality impact and no stated integrity or availability impact.
Likely exposure
Exposure includes the listed Windows 10 and 11 releases and Windows Server 2008 through 2019 variants. Prioritize systems using NTLM that can receive or access attacker-controlled files, names, paths, or network content. The bundle does not establish exposure for unlisted Windows versions.
Exploitation context
The supplied record does not show CISA KEV inclusion or evidence of active exploitation. Exploit maturity is marked unproven. Successful abuse requires user interaction but can originate over a network without authentication, making phishing or attacker-controlled content plausible contexts; specific delivery methods are not documented here.
Researcher notes
The vector is CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C. The description attributes the weakness to attacker control of a file name or path in Windows NTLM. The supplied evidence does not identify affected configurations, specific KB numbers, observed attacks, or whether disclosed hashes are practically reusable.
Mitigation direction
- Apply the Microsoft security update identified in the vendor advisory.
- Review Microsoft guidance for prerequisites and version-specific update details.
- Reduce NTLM usage where operationally feasible and supported by organizational policy.
- Limit outbound authentication to untrusted network destinations using approved defensive controls.
Validation and detection
- Inventory endpoints and servers matching the affected Windows releases.
- Verify each affected system has the Microsoft update installed successfully.
- Identify affected systems where NTLM remains enabled or operationally required.
- Monitor defensive telemetry for unexpected outbound NTLM authentication attempts.
- Confirm unsupported or legacy servers receive applicable vendor-supported servicing guidance.
Public sources used
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-73: File access and web shell behavior lookup
File traversal and upload weaknesses can lead teams to review file, web shell, execution, and collection telemetry. 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 lookupCVE-2026-20925 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
- Medium
- CVSS
- 6.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N/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:L/PR:N/UI:R/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C2.83.6microsoftVulnerability scoring details
Base CVSS 3.1 score
6.5MediumVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N/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
- NTLM Hash Disclosure Spoofing 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.
External Control of File Name or Path
External Control of File Name or Path represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.