CVE-2026-45591 — aspnet-core
CVE-2026-45591 is a Uncontrolled Resource Consumption vulnerability in aspnet-core. A fix is available for aspnet-core — see the affected versions and patch details below.
ASP.NET Core Denial of Service Vulnerability
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-45591.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
Real-World Exposure
aspnet-coreReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Bitnami packages — download data is not available via public APIs for these ecosystems.
Description
Uncontrolled resource consumption in ASP.NET Core allows an unauthorized attacker to deny service over a network.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦Bitnami | aspnet-core | ≥ 8.0.0&&< 8.0.28 | 8.0.28 |
Affected Products
.netmicrosoftasp.net coremicrosoftvisual studio 2026microsoftDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for aspnet-core, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update aspnet-core to 8.0.28 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-45591 is resolved across your whole dependency graph.
Workarounds
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
This vulnerability affects the MessagePack hub protocol implementation used by ASP.NET Core SignalR and Blazor Server. Red Hat Product Security has assessed this issue as an Important severity vulnerability. The flaw occurs when processing deeply nested MessagePack arrays supplied by a remote attacker. Insufficient…
Red Hat is not aware of a practical temporary workaround that fully mitigates this issue or meets Red Hat Product Security's standards for usability, deployment, applicability, or stability. Customers are advised to apply the relevant security updates when they become available.Source: Red Hat security advisory for CVE-2026-45591 (CC BY 4.0)
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat Enterprise Linux 10 | dotnet8.0-0:8.0.128-1.el10_2 | RHSA-2026:25111 |
| Red Hat Enterprise Linux 10 | dotnet9.0-0:9.0.118-1.el10_2 | RHSA-2026:25112 |
| Red Hat Enterprise Linux 10 | dotnet10.0-0:10.0.109-1.el10_2 | RHSA-2026:25115 |
| Red Hat Enterprise Linux 10.0 Extended Update Support | dotnet8.0-0:8.0.128-1.el10_0 | RHSA-2026:28007 |
| Red Hat Enterprise Linux 10.0 Extended Update Support | dotnet9.0-0:9.0.118-1.el10_0 | RHSA-2026:28009 |
| Red Hat Enterprise Linux 8 | dotnet8.0-0:8.0.128-1.el8_10 | RHSA-2026:25110 |
| Red Hat Enterprise Linux 8 | dotnet9.0-0:9.0.118-1.el8_10 | RHSA-2026:25113 |
| Red Hat Enterprise Linux 8 | dotnet10.0-0:10.0.109-1.el8_10 | RHSA-2026:25114 |
Frequently Asked Questions
Is CVE-2026-45591 in your dependencies?
Find it across Bitnami, including transitive dependencies.