9.8

CVE-2026-58617: microsoft 365_copilot Improper Access Control

CVSS: 9.8v3.1CriticalAnalyzed
Published 14-07-2026Last modified 08-10-2026
Open JSON

Vulnerability summary

CVE-2026-58617 is a critical (CVSS 9.8) Improper Access Control vulnerability in microsoft 365_copilot. EPSS estimates a 0.79% chance of exploitation in the next 30 days, higher than 55.3% of scored vulnerabilities.

Overall risk
70/100
0100
High · default modelHow is this calculated?
CVSS score
9.8/10
010
Critical · v3.1 (NVD)
EPSS score
0.79%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 14-07-2026
    PublishedVulnerability first disclosed.
  2. 08-10-2026
    Last modifiedVulnerability information updated.

Description

Improper access control in Microsoft 365 Copilot for iOS allows an unauthorized attacker to elevate privileges over a network.

CVSS metrics

2 scores · 2 sources · 1 version

EPSS trend

Probability

0.79%

Chance of exploitation in the next 30 days

Percentile

55%

Versus all other CVEs

30-day change

0.00 pp

From 0.79% on 19-09-2026

19-09-202619-10-2026
EPSS score
0.79%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Microsoft2 products

1 vendor · 2 products

References

1 links