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HIGH severity

CVE-2026-96940 — Microsoft

HIGH

CVE-2026-96940 is a high-severity (CVSS 8.8) CWE-1390 vulnerability. No vendor fix is recorded yet; mitigation options are listed below.

Weak authorization in Microsoft Exchange Server allows an authenticated attacker to elevate privileges over a network.

Published
Oct 2, 2026
Updated
Oct 2, 2026
Affected
—
Patched
—
Exploits
None indexed
Exploitation data as of Oct 2, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

  • A successful exploit gives an attacker total control of the affected component, not partial access.
  • CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-96940.

Description

Weak authorization in Microsoft Exchange Server allows an authenticated attacker to elevate privileges over a network.

Detection & mitigation playbook

Vulnerability
  1. Detect

    Identify every host running the affected component and compare the installed build against the fixed version below — for source-built or distro-packaged software the version string, not a lockfile, is the source of truth (`dpkg -l`, `rpm -q`, or the binary's own `--version`).

  2. Remediation status

    No fixed release is recorded for CVE-2026-96940 yet. Track the upstream advisory, and apply the exposure-reduction steps below in the meantime.

  3. Mitigate without a patch

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Frequently Asked Questions

Weak authorization in Microsoft Exchange Server allows an authenticated attacker to elevate privileges over a network.
O3 Security · Impact-Aware SCA

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