CVE-2026-96940Important
Microsoft Exchange Server Elevation of Privilege Vulnerability
Assessment
Weak authorization in Microsoft Exchange Server allows an authenticated attacker to elevate privileges over a network.
- Severity
- Important
- CVSS base score
- 8.8CVSS:3.1/
AV:N/ AC:L/ PR:L/ UI:N/ S:U/ C:H/ I:H/ A:H/ E:U/ RL:O/ RC:C - Impact
- Elevation of Privilege
- EPSS, next 30 days
- Not scored yet
- Public exploit code
- No Nuclei template lists it
- Exploitability
- Exploitation More Likely
- Publicly disclosed
- No
- Customer action
- Required: apply the update
- Component
- Microsoft Exchange Server
- Weakness
- CWE-1390: Weak Authentication
- Issued by
- Microsoft
- Published
- 2 Oct 2026 · October 2026
- Last revised
- 2 Oct 2026
Updates that fix it
4 KBs| KB | Type | Restart | Applies to | Other CVEs |
|---|---|---|---|---|
| KB5129955 | Security Update | — | Microsoft Exchange Server Subscription Edition RTM | All CVEs in KB5129955 |
| KB5129956 | Security Update | — | Microsoft Exchange Server 2019 Cumulative Update 15 | All CVEs in KB5129956 |
| KB5129957 | Security Update | — | Microsoft Exchange Server 2019 Cumulative Update 14 | All CVEs in KB5129957 |
| KB5129958 | Security Update | — | Microsoft Exchange Server 2016 Cumulative Update 23 | All CVEs in KB5129958 |