CVE-2023-21538 | .NET Denial of Service Vulnerability

.NET Denial of Service Vulnerability

Published: 2023-01-10 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2023-21538 is rated Moderate Risk (61.1/100): CVSS High severity, with medium exploitation likelihood (EPSS 2.74%). EPSS rose +1.62% over the last day, indicating growing attacker interest. Review affected assets and schedule remediation.

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-2023-21538

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 2026-06-15 1.12% 2.74% +1.62%
2 2026-05-21 0.85% 1.12% +0.27%
3 2026-03-02 — 0.85% —

Full EPSS history (24 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2023-21538

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-2023-21538

GitHub Security Advisory for CVE-2023-21538

GHSA-8f7f-vqg5-jrv9 · Severity: high · Ecosystem: nuget — .NET Denial of Service Vulnerability

OS Trackers for CVE-2023-21538

vendor priority summary link
alpine high CVE-2023-21538: 2 source package rows (dotnet6-build, dotnet6-runtime); 10 state rows across 5 repos (3.17-community, 3.18-community, 3.19-community, 3.20-community, edge-community); fixed 10, open 0. https://security.alpinelinux.org/vuln/CVE-2023-21538
redhat medium — https://access.redhat.com/security/cve/CVE-2023-21538
ubuntu medium CVE-2023-21538 medium priority: Ubuntu including 1 source packages (dotnet6), 7 status rows across 7 suites (bionic, focal, jammy, kinetic, trusty, upstream, xenial): DNE 4, released 3. https://ubuntu.com/security/CVE-2023-21538

Affected software / configurations for CVE-2023-21538

Vendor Product Version Raw CPE
microsoft .net 6.0.0 cpe:2.3:a:microsoft:.net:6.0.0:-:*:*:*:*:*:*
microsoft powershell 7.2 cpe:2.3:a:microsoft:powershell:7.2:*:*:*:*:*:*:*
fedoraproject fedora 36 cpe:2.3:o:fedoraproject:fedora:36:*:*:*:*:*:*:*
fedoraproject fedora 37 cpe:2.3:o:fedoraproject:fedora:37:*:*:*:*:*:*:*

References for CVE-2023-21538

cvelogic Threat Intelligence