CVE-2026-120796 json
.NET Denial of Service Vulnerability
published yesterday modified 17h ago also EUVD-2026-122469 , GHSA-cpw3-h88j-9f6x
- cvss
- 5.3
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 1.2%
- EPSS 1.2% chance of exploitation in 30 days, percentile 67%
- public exploits
- 0
- none known
Summary
Inefficient algorithmic complexity in .NET allows an unauthorized attacker to deny service over a network.
Patch / fix
- nuget Microsoft.NETCore.App.Runtime.linux-arm 11.0.0
- nuget Microsoft.NETCore.App.Runtime.linux-arm64 11.0.0
- nuget Microsoft.NETCore.App.Runtime.linux-musl-arm 11.0.0
- nuget Microsoft.NETCore.App.Runtime.linux-musl-arm64 11.0.0
- nuget Microsoft.NETCore.App.Runtime.linux-musl-x64 11.0.0
- nuget Microsoft.NETCore.App.Runtime.linux-x64 11.0.0
- nuget Microsoft.NETCore.App.Runtime.osx-arm64 11.0.0
- nuget Microsoft.NETCore.App.Runtime.osx-x64 11.0.0
- nuget Microsoft.NETCore.App.Runtime.win-arm64 11.0.0
- nuget Microsoft.NETCore.App.Runtime.win-x64 11.0.0
- nuget Microsoft.NETCore.App.Runtime.win-x86 11.0.0
- nuget System.Text.Json 11.0.0
- Microsoft .NET 11.0 installed on Linux 11.0.0
- Microsoft .NET 11.0 installed on Mac OS 11.0.0
- Microsoft .NET 11.0 installed on Windows 11.0.0
- Microsoft System.Text.Json 11.0.0
Is CVE-2026-120796 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.
Check with FencerCISA SSVC
- Exploitation
- none
- Automatable
- yes
- Technical impact
- partial
- Assessed
- yesterday
Exploit prediction
1.17% chance of exploitation in the next 30 days, higher than 67% of all scored CVEs (FIRST EPSS, 2026-11-11).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L/E:U/RL:O/RC:C |
| GitHub | 3.1 | 5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L/E:U/RL:O/RC:C |
| CNA | 3.1 | 5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| nuget | Microsoft.NETCore.App.Runtime.linux-arm | >=11.0.0-preview.1.26104.118, <11.0.0 |
11.0.0 |
| nuget | Microsoft.NETCore.App.Runtime.linux-arm64 | >=11.0.0-preview.1.26104.118, <11.0.0 |
11.0.0 |
| nuget | Microsoft.NETCore.App.Runtime.linux-musl-arm | >=11.0.0-preview.1.26104.118, <11.0.0 |
11.0.0 |
| nuget | Microsoft.NETCore.App.Runtime.linux-musl-arm64 | >=11.0.0-preview.1.26104.118, <11.0.0 |
11.0.0 |
| nuget | Microsoft.NETCore.App.Runtime.linux-musl-x64 | >=11.0.0-preview.1.26104.118, <11.0.0 |
11.0.0 |
| nuget | Microsoft.NETCore.App.Runtime.linux-x64 | >=11.0.0-preview.1.26104.118, <11.0.0 |
11.0.0 |
| nuget | Microsoft.NETCore.App.Runtime.osx-arm64 | >=11.0.0-preview.1.26104.118, <11.0.0 |
11.0.0 |
| nuget | Microsoft.NETCore.App.Runtime.osx-x64 | >=11.0.0-preview.1.26104.118, <11.0.0 |
11.0.0 |
| nuget | Microsoft.NETCore.App.Runtime.win-arm64 | >=11.0.0-preview.1.26104.118, <11.0.0 |
11.0.0 |
| nuget | Microsoft.NETCore.App.Runtime.win-x64 | >=11.0.0-preview.1.26104.118, <11.0.0 |
11.0.0 |
| nuget | Microsoft.NETCore.App.Runtime.win-x86 | >=11.0.0-preview.1.26104.118, <11.0.0 |
11.0.0 |
| nuget | System.Text.Json | >=11.0.0-preview.1.26104.118, <11.0.0 |
11.0.0 |
Affected products
- Microsoft .NET 11.0 installed on Linux
- Microsoft .NET 11.0 installed on Mac OS
- Microsoft .NET 11.0 installed on Windows
- Microsoft System.Text.Json
Classification
- Weakness
-
- CWE-407 Inefficient Algorithmic Complexity
References
-
msrc.microsoft.com
/update-guide/vulnerability/CVE-2026-120796
vendor-advisory, patch, web
-
github.com
/dotnet/runtime/security/advisories/GHSA-cpw3-h88j-9f6x
web
-
nvd.nist.gov
/vuln/detail/CVE-2026-120796
advisory
-
github.com
/dotnet/announcements/issues/499
web
-
github.com
/dotnet/runtime/issues/137280
web
-
github.com
/dotnet/core/blob/main/release-notes/11.0/11.0.0/11.0.0.md
web
-
github.com
/dotnet/runtime
package
-
github.com
/dotnet/runtime/releases/tag/v11.0.0
web
Sources
- CVE List CVE-2026-120796
- GitHub Advisory GHSA-cpw3-h88j-9f6x
- NVD CVE-2026-120796
Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.