7.5

CVE-2026-21218: microsoft .net

CVSS: 7.5v3.1HighAnalyzed
AliasesUBUNTU-CVE-2026-21218USN-8025-1USN-8025-2
Published 10-02-2026Last modified 19-08-2026
Open JSON

Vulnerability summary

CVE-2026-21218 is a high (CVSS 7.5) vulnerability in microsoft .net. EPSS estimates a 1.01% chance of exploitation in the next 30 days, higher than 62.6% of scored vulnerabilities.

Overall risk
30/100
0100
Medium · default modelHow is this calculated?
CVSS score
7.5/10
010
High · v3.1 (CVE.org)
EPSS score
1.01%
0%100%
Low · -0.02 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 0 · Related 1
CGA-JMRR-7H6F-MQCX

Timeline

  1. 10-02-2026
    PublishedVulnerability first disclosed.
  2. 19-08-2026
    Last modifiedVulnerability information updated.

Description

Improper handling of missing special element in .NET allows an unauthorized attacker to perform spoofing over a network.

CVSS metrics

6 scores · 6 sources · 2 versions

EPSS trend

Probability

1.01%

Chance of exploitation in the next 30 days

Percentile

63%

Versus all other CVEs

30-day change

-0.02 pp

From 1.03% on 19-09-2026

19-09-202619-10-2026
EPSS score
1.01%

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

Ubuntu5 products
  • dotnet10< 10.0.103-10.0.3-0ubuntu1~25.10.1 | < 10.0.103-10.0.3-0ubuntu1~24.04.1
  • dotnet6All versions (No fix recorded)
  • dotnet7All versions (No fix recorded)
  • dotnet8< 8.0.124-8.0.24-0ubuntu1~22.04.1 | < 8.0.124-8.0.24-0ubuntu1~25.10.1 | < 8.0.124-8.0.24-0ubuntu1~24.04.1
  • dotnet9< 9.0.114-9.0.13-0ubuntu1~25.10.1
Microsoft4 products
  • .net≥ 8.0.0, < 8.0.24 | ≥ 9.0.0, < 9.0.13 | ≥ 10.0.0, < 10.0.3
  • .net 10.0≥ 10.0.0, < 10.0.3
  • .net 8.0≥ 8.0.0, < 8.0.24
  • .net 9.0≥ 9.0.0, < 9.0.13
Chainguard3 products
  • dotnet-10< 10.0.103-r0
  • dotnet-8< 8.0.124-r0
  • dotnet-9< 9.0.114-r0
Wolfi3 products
  • dotnet-10< 10.0.103-r0
  • dotnet-8< 8.0.124-r0
  • dotnet-9< 9.0.114-r0
NuGet1 product
  • System.Security.Cryptography.Cose≥ 8.0.0, < 8.0.2 | ≥ 9.0.0, < 9.0.13 | ≥ 10.0.0, < 10.0.3

5 vendors · 16 products

References

10 links