Security readout for executives and security teams
Plain-English summary
CVE-2026-26133 is a Microsoft 365 Copilot information disclosure issue caused by AI command injection. A remote unauthenticated attacker could cause Copilot-related clients to reveal information if user interaction occurs. The business concern is potential exposure of sensitive Microsoft 365 data through affected apps.
Executive priority
High priority for Microsoft 365-heavy organizations, especially where Copilot can access sensitive mail, files, chats, notebooks, or reports. Patch verification should be handled promptly, but the provided evidence does not support emergency active-exploitation language.
Technical view
The source describes AI command injection mapped to CWE-77. CVSS 3.1 is 7.1: network exploitable, low complexity, no privileges required, user interaction required, high confidentiality impact, low integrity impact, and no availability impact. Microsoft lists an official remediation through MSRC.
Likely exposure
Exposure is most likely where users run affected Microsoft 365 Copilot, Office, Edge, Teams, Outlook, Power BI, Loop, or OneNote clients on Android, iOS, or Outlook for Mac. Prioritize environments with Copilot access to sensitive mail, files, chats, notebooks, or BI content.
Exploitation context
The bundle does not show CISA KEV listing or confirmed active exploitation. The CVSS vector marks exploit maturity as unproven and requires user interaction. Treat exploitation as plausible but not confirmed from the provided sources.
Researcher notes
Key constraints are user interaction and information disclosure, with no availability impact. The affected product list is broad across Microsoft mobile clients and Outlook for Mac. The bundle does not include technical exploit details, attack primitives, or precise fixed versions beyond the MSRC advisory reference.
Mitigation direction
- Review the Microsoft MSRC advisory for the official fix and affected product details.
- Update affected Microsoft mobile and Mac clients according to Microsoft guidance.
- Prioritize users with Copilot access to sensitive Microsoft 365 data.
- Limit Copilot access where business need is unclear until updates are verified.
- Monitor Microsoft 365 audit logs for unusual data access or sharing patterns.
Validation and detection
- Inventory affected Microsoft 365 apps on Android, iOS, and Outlook for Mac.
- Confirm installed app versions against Microsoft’s advisory and update channels.
- Identify users licensed for Copilot and map their sensitive data access.
- Check mobile device management compliance for required app update status.
- Review security monitoring for abnormal Copilot-adjacent access events.
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-77: Command execution behavior lookup
Command injection weaknesses can lead defenders to review execution techniques and command interpreter 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 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-2026-26133 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
- 7.1 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/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:L/A:N/E:U/RL:O/RC:C2.84.2microsoftVulnerability scoring details
Base CVSS 3.1 score
7.1HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/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
- M365 Copilot Information Disclosure 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.
Improper Neutralization of Special Elements used in a Command ('Command Injection')
Improper Neutralization of Special Elements used in a Command ('Command Injection') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.