How severe is CVE-2021-41238?

CVE-2021-41238 has a CVSS score of 7.5/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2021-41238?

CVE-2021-41238 affects the following packages: Hangfire.Core (NuGet). Ecosystems affected: NuGet.

How do I fix CVE-2021-41238?

Update Hangfire.Core to 1.7.26 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-41238 is resolved across your whole dependency graph.

How do I detect CVE-2021-41238 in my NuGet dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for Hangfire.Core. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate CVE-2021-41238 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against CVE-2021-41238?

O3 pinpoints whether CVE-2021-41238 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is CVE-2021-41238 actively exploited in the wild?

No public exploit code has been indexed for CVE-2021-41238 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2021-41238?

CVE-2021-41238 has an EPSS (Exploit Prediction Scoring System) score of 0.9%, placing it in the 56th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2021-41238?

CVE-2021-41238 is classified as CWE-862 (CWE-862). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2021-41238 published, and has it been updated?

CVE-2021-41238 was published on November 2, 2021 and was last updated on April 10, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

CVE-2021-41238: Hangfire.Core (High 7.5)

EPSS Exploitation Probability

via FIRST.org ↗

0.9%probability of exploitation in next 30 days

Lower Risk56th percentile+0.64%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Blast Radius

1 pkg affected

.NETHangfire.Core

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects NuGet packages — download data is not available via public APIs for these ecosystems.

Description

Hangfire is an open source system to perform background job processing in a .NET or .NET Core applications. No Windows Service or separate process required. Dashboard UI in Hangfire.Core uses authorization filters to protect it from showing sensitive data to unauthorized users. By default when no custom authorization filters specified, LocalRequestsOnlyAuthorizationFilter filter is being used to allow only local requests and prohibit all the remote requests to provide sensible, protected by default settings. However due to the recent changes, in version 1.7.25 no authorization filters are used by default, allowing remote requests to succeed. If you are using UseHangfireDashboard method with default DashboardOptions.Authorization property value, then your installation is impacted. If any other authorization filter is specified in the DashboardOptions.Authorization property, the you are not impacted. Patched versions (1.7.26) are available both on Nuget.org and as a tagged release on the github repo. Default authorization rules now prohibit remote requests by default again by including the LocalRequestsOnlyAuthorizationFilter filter to the default settings. Please upgrade to the newest version in order to mitigate the issue. For users who are unable to upgrade it is possible to mitigate the issue by using the LocalRequestsOnlyAuthorizationFilter explicitly when configuring the Dashboard UI.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
.NETNuGet	`Hangfire.Core`	≥ 1.7.25&&< 1.7.26	1.7.26

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for Hangfire.Core. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update Hangfire.Core to 1.7.26 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-41238 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2021-41238 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to CVE-2021-41238. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

Hangfire is an open source system to perform background job processing in a .NET or .NET Core applications. No Windows Service or separate process required. Dashboard UI in Hangfire.Core uses authorization filters to protect it from showing sensitive data to unauthorized users. By default when no custom authorization filters specified, `LocalRequestsOnlyAuthorizationFilter` filter is being used to allow only local requests and prohibit all the remote requests to provide sensible, protected by default settings. However due to the recent changes, in version 1.7.25 no authorization filters are us

O3 Security · Impact-Aware SCA

Is CVE-2021-41238 in your dependencies?

O3 detects CVE-2021-41238 across NuGet dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

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CVE-2021-41238