USN-8958-1: Ubuntu Ubuntu vulnerability
It was discovered that the .NET Blazor WebAssembly debug proxy did not properly escape certain values. An attacker could possibly use this issue to execute arbitrary code. The fix for this CVE was originally released via USN-8942-1, but it was found to be incomplete. This issue only affected dotnet10 and dotnet11. (CVE-2026-102870)
It was discovered that the Brotli decompression library used by .NET incorrectly handled certain compressed streams. A remote attacker could possibly use this issue to cause a denial of service or execute arbitrary code. (CVE-2026-111497)
Alen Cheung discovered that .NET did not properly handle file ownership in certain circumstances. An attacker could possibly use this issue to elevate local privileges. (CVE-2026-114148)
Affected Software
Child vulnerabilities
Contains the following vulnerabilities.
Frequently Asked Questions
Which components are exposed to remote attacks?
The Brotli decompression issue can be triggered by a remote attacker and may lead to denial of service or arbitrary code execution. The advisory does not state the access requirements for exploiting the Blazor WebAssembly debug proxy issue.
Are all .NET releases affected by the Blazor WebAssembly debug proxy issue?
No. The advisory states that the incomplete debug-proxy fix issue affects only dotnet10 and dotnet11.
Is a system that received the earlier fix for the debug proxy issue fully protected?
No. The fix originally released in USN-8942-1 for CVE-2026-102870 was found to be incomplete. Systems relying on that earlier fix should apply the updated fix covered by this notice.
Does exploiting the file ownership issue require local access?
The issue concerns file ownership handling and could allow an attacker to elevate local privileges. The advisory characterizes the impact as local privilege escalation rather than remote exploitation.