CVE-2026-55145
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedImproper neutralization of special elements used in a command ('command injection') in Outlook Copilot allows an authorized attacker to perform tampering over a network.
In the news
Third-party coverage- Microsoft July 2026 Patch Tuesday fixes massive 570 flaws, 3 zero-days
- Microsoft CVE Summary - Bleeping Computer
Surfaced from public web coverage — external links open in a new tab.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceCommand injection vulnerability in Outlook Copilot allows an authenticated attacker to inject arbitrary commands through improper handling of special elements in user input processed by the Copilot feature. The vulnerability enables network-based tampering attacks against the affected Outlook Copilot implementation.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE dataall versionsCVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Confirm Outlook Copilot is enabledCheck if Microsoft Copilot or Outlook Copilot feature is enabled in your Microsoft 365 or Outlook environment through admin center or registry settingsAffected if Copilot is actively enabled and processing user requests
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Identify Copilot authentication configurationReview the authentication methods configured for Copilot access - check Azure AD/Entra ID conditional access policies and user licensingAffected if Authenticated users have access to Copilot and can submit input
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Review Copilot processing logsExamine Microsoft 365 audit logs, Exchange audit logs, or Copilot-specific logs for unusual command-like patterns in user prompts or requestsAffected if Logs show malformed input or unexpected command patterns being processed
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Check for anomalous network behaviorMonitor network traffic from Copilot endpoints or service accounts for signs of unexpected command execution or lateral movementAffected if Network logs reveal outbound connections initiated by Copilot service to internal systems or unexpected destinations
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Inspect Copilot service account permissionsReview permissions assigned to the service account running Copilot - check if it has elevated privileges or execution rightsAffected if Service account has more than minimum required permissions, enabling potential command execution impact
Your environment is affected if Outlook Copilot is enabled and accessible to authenticated users, since the vulnerability allows command injection through Copilot user input processing.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataImplement proper input validation and sanitization for all user-supplied data processed by Copilot, employing parameterized queries or safe API calls that treat input as data rather than executable code. Apply principle of least privilege to Copilot service accounts.
- Consultation4.0 h
- Implementation12.0 h
- Testing8.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $7,808.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-55145 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-55145 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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