Important CVSS 6.5 EPSS 0.01315 2026-08 archive

Executive Summary

Deserialization of untrusted data in Microsoft Exchange Server allows an authorized attacker to deny service over a network.

Overview

6.5
CVSS MEDIUM
Important
MS Severity
Not Exploited
MS Exploit Status
Less Likely
MS Exploit Likelihood
Category Denial of Service
Released Aug 11 2026
Last Updated Aug 11 2026
Publicly Disclosed No
CISA KEV Not Listed
Known Exploits None Known
EPSS Score 0.01315 — 0.68208 percentile
NVD CVSS 6.5 MEDIUM — matches MSRC

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C
ATTACK VECTOR
Network
ATTACK COMPLEXITY
Low
PRIVILEGES REQUIRED
Low
USER INTERACTION
None
SCOPE
Unchanged
CONFIDENTIALITY
None
INTEGRITY
None
AVAILABILITY
High
EXPLOIT CODE MATURITY
Unproven
REMEDIATION LEVEL
Official Fix
REPORT CONFIDENCE
Confirmed
Temporal Score: 5.7

EPSS Score

0.01315
probability of exploitation in the next 30 days
0.68208 percentile - updated 2026-08-14
View on FIRST.org

Affected Products

4 affected products
Product KB Article Severity Impact Restart Required
Microsoft Exchange Server 2016 Cumulative Update 23 5121576 (Security Update) Important Denial of Service Yes
Microsoft Exchange Server 2019 Cumulative Update 14 5121575 (Security Update) Important Denial of Service Yes
Microsoft Exchange Server 2019 Cumulative Update 15 5121574 (Security Update) Important Denial of Service Yes
Microsoft Exchange Server Subscription Edition RTM 5121573 (Security Update) Important Denial of Service Yes

Patches

4 patches
Article Type Restart
5121576 Security Update Yes
5121575 Security Update Yes
5121574 Security Update Yes
5121573 Security Update Yes

Known Exploits

Acknowledgments

ECooper with Aretiq.AI