4.3

CVE-2026-66798: microsoft edge_chromium Use After Free

CVSS: 4.3v3.1MediumAnalyzed
Published 28-08-2026Last modified 08-10-2026
Open JSON

Vulnerability summary

CVE-2026-66798 is a medium (CVSS 4.3) Use After Free vulnerability in microsoft edge_chromium. EPSS estimates a 0.79% chance of exploitation in the next 30 days, higher than 55.3% of scored vulnerabilities.

Overall risk
17/100
0100
Low · default modelHow is this calculated?
CVSS score
4.3/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.79%
0%100%
Low · +0.23 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 28-08-2026
    PublishedVulnerability first disclosed.
  2. 08-10-2026
    Last modifiedVulnerability information updated.

Description

Use after free in Microsoft Edge (Chromium-based) allows an unauthorized attacker to execute code 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

+0.23 pp

From 0.56% 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

Microsoft7 products

1 vendor · 7 products

References

1 links