# CVE-2026-62911: Microsoft Exchange Server Elevation of Privilege Vulnerability

- Exploited (CISA KEV): no
- Published: 2026-08-11
- CVSS: 8 HIGH (v3.1)
- EPSS: 0.7% (53th percentile)
- CWE: CWE-294

Authentication bypass by capture-replay in Microsoft Exchange Server allows an authorized attacker to elevate privileges over a network.

## Edge WAF coverage (claimed by vendors, not measured)

| Vendor | Status | First rule | Days after publication |
|---|---|---|---|
| Cloudflare | No public claim | — | — |
| AWS | No public claim | — | — |
| Microsoft Azure | No public claim | — | — |
| Google Cloud | No public claim | — | — |
| Fastly | Before feed history | — | — |
| F5 | Rule published | 2026-10-21 | 71 |
| Akamai | No public source | — | — |
| OWASP CRS | No public claim | — | — |

### F5

- 2026-10-21 · new · rule 200013238
  > Added: signature 200013238 "Microsoft Exchange MRSProxy Authentication Bypass" (Authentication/Authorization Attacks, risk High), systems: Outlook Web Access. References: CVE-2026-62911.
  Source: https://docs.cloud.f5.com/docs-v2/platform/changelogs/security-details-changelog

## Social

1 posts seen since 2026-11-02.

- Exploit repository (unvetted): https://github.com/c5z54/cve-2026-62911-poc

"No public claim" means no vendor statement names this CVE; "Before feed history" means the CVE is older than the vendor feed. In both cases generic rules may still block it.

HTML: https://cve.vigilbase.com/cve/CVE-2026-62911 · JSON: https://cve.vigilbase.com/api/v1/cves/CVE-2026-62911