CVE-2026-41100: Improper access control in M365 Copilot allows an authorized attacker to perform spoofing locally.

Q: How do I fix CVE-2026-41100?

365 copilot: upgrade to 16.0.19822.20190. Exact commands for each OS are on this page.

Q: Is CVE-2026-41100 being exploited?

CVE-2026-41100 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-41100 affect?

CVE-2026-41100 affects 365 copilot. Severity is medium (CVSS 4.4). Improper access control in M365 Copilot allows an authorized attacker to perform spoofing locally.

Q: How urgent is CVE-2026-41100?

Priority 24/100. On your watchlist

Routine

MEDIUM 4.4WATCHLISTUPGRADE

CVE-2026-41100 is a medium-severity flaw (CVSS 4.4) affecting 365 copilot. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Improper access control in M365 Copilot allows an authorized attacker to perform spoofing locally.

Why this priority

On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	4.4 (Medium)
Attack vector	Local
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.2% (top 84%)
CISA exploited list	No
Weakness	CWE-284
Published	2026-05-12
Last modified	2026-10-26

Publisher (CNA): Microsoft Corporation · Vendor: microsoft

Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-05-12 18:17 UTCPublished CVE record published
2026-10-26 18:10 UTCUpdated Record last modified

microsoft 365 copilot UPGRADE

Affected: < 16.0.19822.20190

Fixed in: 16.0.19822.20190

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy 365-copilot || rpm -q 365-copilot || 365-copilot --version

2. UPGRADE to 16.0.19822.20190 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade 365-copilot

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade 365-copilot

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-41100?

365 copilot: upgrade to 16.0.19822.20190. Exact commands for each OS are on this page.

Is CVE-2026-41100 being exploited?

CVE-2026-41100 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-41100 affect?

CVE-2026-41100 affects 365 copilot. Severity is medium (CVSS 4.4). Improper access control in M365 Copilot allows an authorized attacker to perform spoofing locally.

How urgent is CVE-2026-41100?

Priority 24/100. On your watchlist

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References

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