Security readout for executives and security teams
Plain-English summary
A remote, unauthenticated attacker could exploit a memory-handling flaw in Windows Remote Desktop Services to run code on an affected server. Successful compromise could expose data, alter systems, or interrupt services. Exploitation is rated difficult, but no user action or prior access is required.
Executive priority
Prioritize exposed or business-critical Remote Desktop servers for prompt review and patching. The absence of confirmed exploitation tempers emergency escalation, but unauthenticated remote code execution and potentially complete system impact justify accelerated remediation.
Technical view
CVE-2025-26671 is a use-after-free vulnerability in Windows Remote Desktop Services, classified as CWE-416 and CWE-591. Its CVSS 3.1 score is 8.1: network-accessible, unauthenticated, no user interaction, high attack complexity, and potentially high confidentiality, integrity, and availability impact.
Likely exposure
Exposure is most likely where affected Windows Server 2008 R2 through Windows Server 2025 systems, including listed Server Core editions, run reachable Remote Desktop Services. The bundle does not establish whether every affected installation is exploitable by default.
Exploitation context
The bundle does not identify active exploitation, and the CVE is not listed as CISA KEV. CVSS marks exploit maturity as unproven and attack complexity as high. These factors reduce immediate likelihood but do not remove the potential for severe unauthenticated remote impact.
Researcher notes
The supplied evidence confirms a network-reachable use-after-free with high attack complexity and no required privileges or interaction. It does not provide triggering conditions, affected RDS components, proof-of-concept availability, observed exploitation, or specific update identifiers. Consult Microsoft’s advisory for release-specific remediation details.
Mitigation direction
- Identify affected Windows Server systems and determine whether Remote Desktop Services is enabled or network-reachable.
- Review Microsoft’s CVE advisory for applicable security updates and installation requirements.
- Apply the relevant Microsoft security update using established emergency-patching procedures.
- Restrict unnecessary network access to Remote Desktop Services while remediation is pending.
Validation and detection
- Inventory listed Windows Server versions, including Server Core installations.
- Confirm whether Remote Desktop Services is enabled and which networks can reach it.
- Verify the applicable Microsoft security update is installed successfully on each exposed asset.
- Re-scan patched systems and investigate update failures or unexpectedly reachable services.
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 lookupCWE-591: 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-2025-26671 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
- 8.1 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/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:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C2.25.9microsoftVulnerability scoring details
Base CVSS 3.1 score
8.1HighVector: CVSS:3.1/AV:N/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
- Windows Remote Desktop Services 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.