Security readout for executives and security teams
Plain-English summary
CVE-2026-26112 is a high-severity Microsoft Excel remote code execution issue. A victim must interact with affected Office content, but successful exploitation could let an attacker run code on the user’s system. This matters most where employees frequently receive external spreadsheets or Office files.
Executive priority
Treat this as a near-term patching priority, especially for users who open external spreadsheets. The issue is high impact, but current provided evidence does not indicate known active exploitation.
Technical view
Microsoft describes an untrusted pointer dereference in Microsoft Office Excel that allows an unauthorized attacker to execute code locally. The CVSS 3.1 score is 7.8 with local attack vector, low complexity, no privileges required, and user interaction required. Affected products include Excel 2016, Office 2019, Office LTSC 2021/2024, Microsoft 365 Apps for Enterprise, Mac LTSC editions, and Office Online Server.
Likely exposure
Organizations are exposed if they run the affected Microsoft Excel, Office, Microsoft 365 Apps, Office LTSC for Mac, or Office Online Server versions listed by Microsoft and have not applied the relevant vendor update.
Exploitation context
The source bundle does not show active exploitation, and KEV status is false. Exploitation requires user interaction per CVSS, so phishing or file-sharing scenarios are the most relevant business risk, but no specific campaign is cited in the provided sources.
Researcher notes
Key facts come from Microsoft and CVE records. The weakness is CWE-822, untrusted pointer dereference. CVSS indicates local vector and required user interaction, not network wormability. Patch details beyond the MSRC advisory are not included in the provided bundle.
Mitigation direction
- Review the Microsoft MSRC advisory for the applicable update.
- Apply Microsoft’s security update to affected Office and Excel installations.
- Prioritize endpoints handling external spreadsheets or untrusted Office files.
- Include Office Online Server in patch scope if deployed.
- Use standard controls for untrusted attachments until patched.
Validation and detection
- Inventory installed Microsoft Office and Excel versions.
- Compare assets against Microsoft’s affected product list.
- Confirm the relevant Microsoft update is installed.
- Check Office Online Server separately if present.
- Document systems that cannot be updated immediately.
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-822: 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-2026-26112 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
- 7.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/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.
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:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C1.85.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.8HighVector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
Source materials
- CVE List V5 sourceCVE List V5
- Microsoft Excel Remote Code Execution VulnerabilityCVE reference · 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.
Untrusted Pointer Dereference
Untrusted Pointer Dereference represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.