Security readout for executives and security teams
Plain-English summary
This Microsoft Windows RD Gateway issue can cause a denial of service, meaning affected systems may become unavailable. The provided sources rate it medium severity with high availability impact, but no confidentiality or integrity impact. It is not listed as CISA KEV, and the bundle provides no evidence of active exploitation.
Executive priority
Handle through normal monthly patch governance, with higher priority for RD Gateway systems supporting business remote access. The main business risk is service disruption, not data theft based on the provided sources.
Technical view
CVE-2025-21278 is a CWE-362 race condition in Windows Remote Desktop Gateway. CVSS 3.1 is 6.2 with local attack vector, low complexity, no privileges, no user interaction, unchanged scope, and high availability impact only. Microsoft lists updates as available for affected Windows client and server versions.
Likely exposure
Exposure is most relevant to organizations running the listed Microsoft Windows versions, especially systems where RD Gateway is present or relied on for remote access. Validate actual exposure through asset inventory, installed roles, and patch status rather than assuming every listed Windows host is exploitable.
Exploitation context
The source bundle marks KEV as false and CVSS exploit maturity as unproven. No cited source states active exploitation or provides public exploit details. Treat this as an availability risk requiring patch management attention, not as a confirmed in-the-wild compromise signal.
Researcher notes
The key technical clue is CWE-362, indicating a race condition. The CVSS vector limits impact to availability and records local attack vector. The public bundle does not include root-cause detail, crash conditions, exploit primitives, or named mitigations beyond Microsoft updates.
Mitigation direction
- Apply the Microsoft security update for affected Windows versions.
- Prioritize RD Gateway servers and critical remote-access infrastructure.
- Use MSRC guidance for exact affected builds and update applicability.
- If patching is delayed, check Microsoft guidance for supported compensating controls.
Validation and detection
- Inventory Windows hosts matching the affected versions listed by Microsoft.
- Identify systems with RD Gateway installed, enabled, or operationally required.
- Confirm the relevant Microsoft security update is installed.
- Track unresolved RD Gateway hosts as availability-risk exceptions until remediated.
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-362: 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 lookupCVE-2025-21278 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
- 6.2 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/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:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C2.53.6microsoftVulnerability scoring details
Base CVSS 3.1 score
6.2MediumVector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/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 Gateway (RD Gateway) Denial of Service 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.
Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.