CVE-2026-87696

Improper verification of cryptographic signature in Microsoft Exchange Server allows an authorized…

Risk score: 61/100
CVSS: 7.5 v3.1
Exploit chance (30 days): 0.4%
Published: 13 Oct 2026

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What to know

What it is: Improper verification of cryptographic signature in Microsoft Exchange Server allows an authorized attacker to elevate privileges over a network.
Affected: See advisory
Fix: Apply the vendor's security update; see the linked advisory.
Exploitation: No known exploitation

Why it is Amber

CVSS 7.5 high
On your watchlist: exchange server

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-87696

Original description

Improper verification of cryptographic signature in Microsoft Exchange Server allows an authorized attacker to elevate privileges over a network.

Last activity 13 Oct 2026. Patch Forecast updates every hour.