Security readout for executives and security teams
Plain-English summary
An unauthenticated remote attacker could abuse command-handling flaws associated with M365 Copilot to alter data through Microsoft Outlook for iOS. Exploitation requires user interaction. The reported impact is serious integrity loss, but not confidentiality or availability loss.
Executive priority
Prioritize verification and remediation promptly because unauthenticated network access and high integrity impact increase business risk. Treat this as high priority, not an emergency based on exploitation evidence, because active exploitation is not established.
Technical view
CVE-2026-42893 is a CWE-77 command-injection vulnerability with CVSS 3.1 score 7.4. It is network-accessible, low complexity, requires no privileges, and needs user interaction. Scope may cross a security boundary, with high integrity impact. The supplied product and description differ on whether the vulnerable component is Outlook for iOS or M365 Copilot.
Likely exposure
The bundle lists Microsoft Outlook for iOS version 1.0.0 as affected, while the description identifies M365 Copilot. Organizations using Outlook for iOS should review Microsoft’s advisory and inventory mobile deployments. The evidence provided does not establish whether later versions, other platforms, or all Copilot configurations are affected.
Exploitation context
The CVSS vector reports remote, unauthenticated, low-complexity exploitation requiring user interaction. CISA KEV status is false, and the vector marks exploit maturity as unproven. Therefore, the supplied evidence does not support claiming active exploitation or publicly demonstrated exploitation.
Researcher notes
The source bundle contains a material attribution ambiguity: the affected entry names Outlook for iOS version 1.0.0, while the description locates command injection in M365 Copilot. Microsoft’s advisory is tagged as providing a patch, but no corrected version or specific mitigation is supplied here. Confirm technical scope directly with Microsoft before testing or asserting exposure.
Mitigation direction
- Review the Microsoft advisory for confirmed affected versions, prerequisites, and the officially corrected release.
- Update managed Outlook for iOS installations according to Microsoft guidance.
- Use mobile-device management to enforce the approved application version where available.
- Assess whether M365 Copilot exposure requires additional Microsoft-recommended controls.
Validation and detection
- Inventory Outlook for iOS versions across managed and supported personal devices.
- Compare deployed versions and configurations against the current Microsoft advisory.
- Confirm update enforcement and installation through mobile-device management reporting.
- Review relevant telemetry for unexplained integrity changes without attempting exploitation.
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-2026-42893 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:N/AC:L/PR:N/UI:R/S:C/C:N/I:H/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:C/C:N/I:H/A:N/E:U/RL:O/RC:C2.84microsoftVulnerability scoring details
Base CVSS 3.1 score
7.4HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:H/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
- Microsoft Outlook for iOS Tampering 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.