The vendor has published a fix. Version details are below where the sources state them.
Steps
Written by AI from the record
Check whether you are running any vulnerable versions of .NET or using the listed Visual Studio 2022/2026 versions (the ones that are not yet on the fixed releases).
Upgrade .NET 10.0 to 10.0.11 or later.
Upgrade .NET 9.0 to 9.0.19 or later.
Upgrade .NET 8.0 to 8.0.30 or later (and note this also covers the “.net” entry).
Upgrade Microsoft Visual Studio 2022 version 17.14 to 17.14.38 or later.
Upgrade Microsoft Visual Studio 2026 version 18.8 to 18.8.3 or later.
Unchecked input for loop condition in .NET allows an unauthorized attacker to deny service over a network.
In plain language
Written by AI from the record
CVE-2026-62901 is a .NET bug that lets someone on the network crash or freeze your app by sending specially crafted data, without needing logins—so most small businesses using vulnerable .NET versions should act.
In .NET, CVE-2026-62901 is a network-triggered denial-of-service where specially crafted input can cause an excessive or infinite loop (CWE-606), allowing a remote attacker with no authentication to stop the .NET system from working.
If you're affected
Website or app downtime
Service slowdown or hangs
Operational disruption
Lost revenue during outages
What is it
Think of your .NET app as following a set of instructions (a loop). This bug lets an attacker feed in weird data so the instructions can repeat far too long (or endlessly), which can freeze or crash the app. The result is downtime—your customers may see errors or timeouts.
Who is affected
This matters if your business runs or builds software using .NET 8.0, .NET 9.0, or .NET 10.0, or you rely on the specific Microsoft Visual Studio 2022/2026 versions listed. Because the issue is reachable over the network with no login and no user action, it’s most relevant for any service that accepts network requests and processes attacker-controlled data.
It’s a risk when an attacker can send data to a network endpoint that your .NET code processes (it’s reachable in default configuration).
How urgent is it
Red: attackers can trigger this remotely without logins, and it can stop the .NET system from working via an infinite or excessive loop. That makes it directly useful for causing downtime. Even without confirmed public exploit code, the impact is immediate when the vulnerable code path is reachable over the network, so you should patch on an urgent schedule.
What to do — in detail
Confirm exposure
Identify every place your business uses .NET: production apps, background services, APIs, and any web endpoints.
Check the runtime version installed on servers/containers. Also check development/build machines if they deploy artifacts from Visual Studio.
Verify whether you have any of the affected versions:
.NET 10.0 (needs 10.0.11+)
.NET 9.0 (needs 9.0.19+)
.NET 8.0 (needs 8.0.30+; this also matches “.net”)
Microsoft Visual Studio 2022 version 17.14 (needs 17.14.38+)
Microsoft Visual Studio 2026 version 18.8 (needs 18.8.3+)
Patch / upgrade (target fixed versions)
Upgrade .NET 10.0 to 10.0.11 or later.
Upgrade .NET 9.0 to 9.0.19 or later.
Upgrade .NET 8.0 to 8.0.30 or later.
Upgrade Visual Studio 2022 version 17.14 to 17.14.38 or later.
Upgrade Visual Studio 2026 version 18.8 to 18.8.3 or later.
Reduce exposure by limiting which network endpoints accept external requests and ensuring only necessary endpoints are reachable from the internet.
Add or tighten rate limiting and request size/time limits at the reverse proxy/load balancer (to reduce the chance of a crafted input causing an excessive loop to tie up resources).
Monitor for service hangs/timeouts and high CPU usage during unexpected request bursts, then block the offending sources if identified.
What to monitor after upgrading
Application health metrics (availability, response times) for regressions.
Logs for unusual request patterns or repeated failures from specific IPs.
KEV / deadlines
This CVE is not listed in CISA KEV in the provided findings, so there is no specific CISA due date mentioned here.
Technical context
CVE-2026-62901 is a denial-of-service issue (CWE-606) in .NET where specially crafted network input can lead to an excessive or infinite loop due to improper handling of a loop termination condition. The findings state:
Remote attacker capability over the network
No authentication required
No user interaction required
Reachable in default configuration
Preconditions: attacker can send data to a network endpoint processed by .NET
Exploit status: no public exploit code was found in the provided findings, and no clearly dated press claim was provided linking this specific CVE to active exploitation. The findings include “press attention” mentioning the patch and an actor name (Lazarus group), but there is no KEV listing and no explicit evidence in the provided data of real-time exploitation.
Fix availability: fixed versions are provided per product branch—.NET 10.0 (10.0.11), .NET 9.0 (9.0.19), .NET 8.0 (8.0.30), and specific Visual Studio versions (17.14.38 and 18.8.3).
KEV meaning (in this case): since it is not in CISA KEV based on the provided findings, there is no mandated “known exploited” indicator from KEV here.
This is a general assessment based on public vulnerability data. It does not account for your specific infrastructure — when in doubt, consult a security specialist.
