CVE-2026-42899 | ASP.NET Core Denial of Service Vulnerability

Loop with unreachable exit condition ('infinite loop') in ASP.NET Core allows an unauthorized attacker to deny service over a network.

Published: 2026-05-12 Last update: 2026-05-13 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-42899 is rated Low Risk (34.1/100): CVSS High severity, with low exploitation likelihood (EPSS 0.04%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-42899

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-05-13 — 0.04% —

Full EPSS history (1 record total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-42899

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 [email protected]

Weakness enumeration for CVE-2026-42899

GitHub Security Advisory for CVE-2026-42899

GHSA-9v76-4qcc-frgh · Severity: high · Ecosystem: nuget — Microsoft Security Advisory CVE-2026-42899 – ASP.NET Core Denial of Service Vulnerability

OS Trackers for CVE-2026-42899

vendor priority summary link
ubuntu medium CVE-2026-42899 medium priority: Ubuntu including 5 source packages (dotnet10, dotnet6, dotnet7, dotnet8, dotnet9), 45 status rows across 9 suites (bionic, focal, jammy, noble, questing, resolute, trusty, upstream, xenial): DNE 31, released 10, needs-triage 2, deferred 1, ignored 1. https://ubuntu.com/security/CVE-2026-42899

Affected software / configurations for CVE-2026-42899

Vendor Product Version Raw CPE
microsoft .net >= 8.0.0, < 8.0.27 cpe:2.3:a:microsoft:.net:*:*:*:*:*:*:*:*
microsoft .net >= 9.0.0, < 9.0.16 cpe:2.3:a:microsoft:.net:*:*:*:*:*:*:*:*
microsoft .net >= 10.0.0, < 10.0.8 cpe:2.3:a:microsoft:.net:*:*:*:*:*:*:*:*

References for CVE-2026-42899

cvelogic Threat Intelligence