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.
Written by anthropic/claude-sonnet-5.5 from the sources below. Verify against them.
- Exploited
- Yes, on CISA KEV
- Fix
- Fixed in 16.0.14334.21048, 16.0.17932.21140
- Who is exposed
- Specific setups only
Do first: Upgrade to a fixed version: 16.0.14334.21048, 16.0.17932.21140.
- Last modified
- Whether it needs action now or is a reference record, by fixed rules, with why. Last checked is when cve.now last re-read it.What do these mean? →
- Added to CISA KEV Nov 10; federal deadline Nov 24
- Last checked
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 69/100 · provisional
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Actively exploited
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
- Exploitation: active
- Automatable: no
- Technical impact: partial
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.
Read the original description
Product ui does not warn user of unsafe actions in Microsoft Office Outlook allows an unauthorized attacker to perform spoofing over a network.
Who should check
Teams running Microsoft Outlook from Microsoft 365 Apps for Enterprise, Office LTSC 2021 or Office LTSC 2024.
Read the source excerpt
“Microsoft Office Outlook contains a missing user interaction for potentially unsafe action vulnerability”
cve.now Index
- Exploitation40/40Listed in CISA's Known Exploited Vulnerabilities catalog
- Exposure22/25Actively exploited, reachable over the network without a login
- Reach?/20Unknown. No tracked technology or package matched
- Severity6.5/10CVSS 6.5
- No patch0/5No signal
What to do
Upgrade to a fixed version: 16.0.14334.21048, 16.0.17932.21140.
Fix it by , CISA's deadline for US federal agencies.
Check your systems with an agent
Paste this into a coding or ops agent. It checks your systems read-only and reports a table per asset.
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.
Timeline
- Added to CISA KEV
CISA has evidence of exploitation in the wild
- CVE published
- cve.now early warning
Microsoft patches record 1,235 flaws, including exploited Outlook zero-day
- CISA SSVC assessment
Exploitation: active · Automatable: no · Technical impact: partial
- First seen by cve.now
- Posted on X by cve.now
- Record last updated14 days
- CISA remediation deadline
Due date for US federal agencies to patch
Affected versions
- 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
Evidence 5
Vendor advisory · 1
Establishes: Affected and fixed versions.
- Patch
CVE record · 2
Establishes: The identifier and description.
- Record
- Record
CISA KEV · 2
Establishes: Exploitation in the wild, for this CVE only.
- Listing
- Link
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-124194
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: cisa.gov, cve.now feed data
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: cisa.gov
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: cve.now feed data
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: cisa.gov
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: cisa.gov