Security readout for executives and security teams
Plain-English summary
This is a high-severity Windows local privilege escalation flaw. An attacker who can run code on an affected device may be able to gain higher privileges. It is not described as remotely exploitable from the network, but it can increase the impact of malware or an initial workstation compromise.
Executive priority
Prioritize remediation in the normal high-severity Windows patch process, with faster handling for shared workstations, developer machines, and servers where local access is plausible. No source provided confirms active exploitation.
Technical view
CVE-2026-25167 is a use-after-free issue in Microsoft Brokering File System. The CVSS 3.1 vector is local, high complexity, no privileges required, no user interaction, unchanged scope, with high confidentiality, integrity, and availability impact. Microsoft lists an official remediation state as available.
Likely exposure
Exposure is limited to the listed Microsoft platforms: Windows 11 24H2, 25H2, 26H1, Windows Server 2025, and Windows Server 2025 Server Core at the specified builds. The source bundle does not name other affected Windows versions.
Exploitation context
The provided sources do not show active exploitation, and the CVE is not marked as KEV. Microsoft’s CVSS data lists exploit code maturity as unproven. Treat this as a serious post-compromise escalation risk, not a confirmed in-the-wild campaign.
Researcher notes
Evidence supports a local EoP use-after-free in Microsoft Brokering File System with official Microsoft remediation. The bundle does not provide root-cause detail, attack primitives, proof-of-concept status, or post-patch behavioral indicators.
Mitigation direction
- Apply the Microsoft security update referenced by the MSRC advisory.
- Prioritize affected endpoints and Windows Server 2025 systems with local user access.
- Track MSRC revisions for any changed affected-product or mitigation guidance.
- Maintain least-privilege controls to limit damage from local code execution.
Validation and detection
- Inventory Windows hosts for the affected product versions and builds.
- Verify patch compliance against Microsoft’s CVE-2026-25167 advisory.
- Confirm Server Core installations are included in remediation tracking.
- Review endpoint telemetry for unexplained privilege changes or post-compromise activity.
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-416: 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 lookupPrivilege behavior lookup
The CVE wording references privilege impact, so privilege escalation and authorization behavior review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2026-25167 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
- 7.4 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:H/PR:N/UI:N/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:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C1.45.9microsoftVulnerability scoring details
Base CVSS 3.1 score
7.4HighVector: CVSS:3.1/AV:L/AC:H/PR:N/UI:N/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
- Microsoft Brokering File System Elevation of Privilege 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.
Use After Free
Use After Free represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.