How severe is GHSA-g5c6-w479-93xm?

No CVSS score has been assigned to GHSA-g5c6-w479-93xm yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by GHSA-g5c6-w479-93xm?

GHSA-g5c6-w479-93xm affects the following packages: mono (NuGet). Ecosystems affected: NuGet.

How do I fix GHSA-g5c6-w479-93xm?

Update mono to 2.6.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-g5c6-w479-93xm is resolved across your whole dependency graph.

How do I detect GHSA-g5c6-w479-93xm in my NuGet dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for mono, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate GHSA-g5c6-w479-93xm if there is no patch (or I can't update yet)?

Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Is GHSA-g5c6-w479-93xm actively exploited in the wild?

No public exploit code has been indexed for GHSA-g5c6-w479-93xm 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 GHSA-g5c6-w479-93xm?

GHSA-g5c6-w479-93xm has an EPSS (Exploit Prediction Scoring System) score of 1.9%, placing it in the 80th 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 GHSA-g5c6-w479-93xm?

GHSA-g5c6-w479-93xm is classified as Cross-site Scripting (XSS) (CWE-79). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was GHSA-g5c6-w479-93xm published, and has it been updated?

GHSA-g5c6-w479-93xm was published on May 2, 2022 and was last updated on January 19, 2024. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

Mono ASP.NET View State Cross-Site Scripting (XSS)…

EPSS Exploitation Probability

via FIRST.org ↗

1.9%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs80th percentile — riskier than 80% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

1 pkg affected

.NETmono

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

The default configuration of ASP.NET in Mono before 2.6.4 has a value of FALSE for the EnableViewStateMac property, which allows remote attackers to conduct cross-site scripting (XSS) attacks, as demonstrated by the __VIEWSTATE parameter to 2.0/menu/menu1.aspx in the XSP sample project.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
.NETNuGet	`mono`	all versions	2.6.4`dotnet add package mono --version 2.6.4`

Affected Products

1 product · 62 configurations

Application

monomono

62 versions

1.01.0.11.0.21.0.41.0.51.0.61.1.11.1.21.1.31.1.41.1.51.1.6

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for mono, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update mono to 2.6.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-g5c6-w479-93xm is resolved across your whole dependency graph.
Workarounds
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Frequently Asked Questions

The default configuration of ASP.NET in Mono before 2.6.4 has a value of FALSE for the EnableViewStateMac property, which allows remote attackers to conduct cross-site scripting (XSS) attacks, as demonstrated by the __VIEWSTATE parameter to 2.0/menu/menu1.aspx in the XSP sample project.

O3 Security · Impact-Aware SCA

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Mono ASP.NET View State Cross-Site Scripting (XSS) vulnerabilityGHSA-g5c6-w479-93xm