No exploitation reportedFix available

CVE-2026-42899

Q: Is CVE-2026-42899 actively exploited?

Active exploitation of CVE-2026-42899 has not been confirmed. Its EPSS score was 2.4% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

Q: What is the CVSS score for CVE-2026-42899?

CVE-2026-42899 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

No exploitation reported by the sources we read.

Published2026-05-12
Fixed in10.0.8 · 9.0.16 · 8.0.27
WeaknessCWE-835

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

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

Timeline

dates in UTC

2026-05-1218:17CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2026-42899?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2026-42899?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD · OSV

Microsoft .netversion to verify

Branch	Affected	Fixed in	Source
10.0	≥ 10.0.0, < 10.0.8	10.0.8	NVD · OSV
9.0	≥ 9.0.0, < 9.0.16	9.0.16	NVD · OSV
8.0	≥ 8.0.0, < 8.0.27	8.0.27	NVD · OSV

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

dotnetAlmaLinux:8all versions · fixed in 10.0.108-1.el8_10and 5 other packages
dotnet-hostAlmaLinux:10all versions · fixed in 10.0.8-1.el10_2and 8 other packages
dotnet-hostAlmaLinux:9all versions · fixed in 10.0.8-1.el9_8and 8 other packages
dotnet-hostAlmaLinux:8all versions · fixed in 10.0.8-1.el8_10and 8 other packages
dotnet-hostfxr-8.0AlmaLinux:10all versions · fixed in 8.0.27-1.el10_2and 7 other packages
dotnet-hostfxr-8.0AlmaLinux:9all versions · fixed in 8.0.27-1.el9_8and 7 other packages
dotnet-hostfxr-8.0AlmaLinux:8all versions · fixed in 8.0.27-1.el8_10and 7 other packages
dotnet-hostfxr-9.0AlmaLinux:10all versions · fixed in 9.0.16-1.el10_2and 7 other packages

10 more package ranges on OSV.dev

Vendor advisories

CVE-2026-42899 Red Hat Product Security1,437 products fixed
dotnet: .NET: infinite loop allows an attacker to cause a denial of service
RHSA-2026:24335 Red Hat Product Security97 products fixed
Red Hat Security Advisory: .NET 8.0 security update
RHSA-2026:24336 Red Hat Product Security119 products fixed
Red Hat Security Advisory: .NET 9.0 security update
RHSA-2026:24334 Red Hat Product Security81 products fixed
Red Hat Security Advisory: .NET 8.0 security update
RHSA-2026:24333 Red Hat Product Security111 products fixed
Red Hat Security Advisory: .NET 9.0 security update
RHSA-2026:24332 Red Hat Product Security89 products fixed
Red Hat Security Advisory: .NET 8.0 security update

12 more advisories

Full record on NVD

Fix

Update Microsoft .net to 10.0.8 · 9.0.16 · 8.0.27
Vendor fix Red Hat Product Security RHSA-2026:24335 · 97 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
Vendor fix Red Hat Product Security RHSA-2026:17682 · 1 productFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://images.redhat.com/
Workaround from the vendor Red Hat Product Security RHSA-2026:24335 · 97 productsRed Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update the affected package as soon as possible.

Advisories and patches

msrc.microsoft.comVendor Advisory

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

NVDCVE recordread 2026-10-23
CISA-ADPSSVC decisionnone2026-05-12
OpenCVESSVC decisionnone—
CNACVSS 3.17.5read 2026-10-23
CNAweakness (CWE)CWE-835read 2026-10-23
FIRST EPSSEPSS score2.4 %2026-10-22
OSVaffected packages—
Microsoft MSRCadvisory—

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published: 2026-05-12
Last Modified: 2026-07-15
NVD status: Modified
MSRC Title: ASP.NET Core Denial of Service Vulnerability

Frequently asked questions

What is CVE-2026-42899?

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

Is CVE-2026-42899 actively exploited?

Active exploitation of CVE-2026-42899 has not been confirmed. Its EPSS score was 2.4% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-42899?

CVE-2026-42899 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Running dotnet? Hear about its next vulnerability

Surveillance reads the versions in your stack — a domain, a lockfile or a list — checks each CVE against the ranges its sources publish, and alerts you when one you run is exploited or enters CISA KEV. A version it cannot read stays « version not verified ».

Get alerts for this product CISA KEV additions, October 2026 Search CVEs

No credit card required · No monthly cap on website lookups · 250 API requests/month

Go further

Following what attackers exploit right now? The CISA KEV additions of the month, with their patch deadlines.
Running this software? Vulnerability monitoring alerts you to new vulnerabilities in your products.

Related vulnerabilities

Same product first, then the same vendor advisory and the same publication week.

Back to CVE Database