How severe is CVE-2021-46703?

CVE-2021-46703 has a CVSS score of 9.8/10, rated CRITICAL. Immediate patching is strongly recommended.

Which packages are affected by CVE-2021-46703?

CVE-2021-46703 affects the following packages: RazorEngine (NuGet). Ecosystems affected: NuGet.

How do I fix CVE-2021-46703?

No patched version of RazorEngine has shipped for CVE-2021-46703 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.

How do I detect CVE-2021-46703 in my NuGet dependencies?

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

How do I mitigate CVE-2021-46703 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.

Is CVE-2021-46703 actively exploited in the wild?

Yes. There are 1 known exploit references for CVE-2021-46703, including 1 in-the-wild exploitation observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2021-46703?

CVE-2021-46703 has an EPSS (Exploit Prediction Scoring System) score of 1.9%, placing it in the 79th 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.

When was CVE-2021-46703 published, and has it been updated?

CVE-2021-46703 was published on March 6, 2022 and was last updated on July 8, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

.NET

.NET NuGet

Not in CISA KEV

CRITICAL severity

CVE-2021-46703 — RazorEngine

CRITICAL

CVE-2021-46703 is a critical-severity (CVSS 9.8) vulnerability in RazorEngine. 1 public exploit reference exists, so weaponization risk is real. No vendor fix is recorded yet; mitigation options are listed below.

Code injection in RazorEngine

Also known asGHSA-ph3v-2hq5-5qfq

Published

Mar 6, 2022

Updated

Jul 8, 2026

Affected

1 pkg

Patched

See advisory

Exploits

1 known

Exploitation data as of Oct 4, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

1.9%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs79th percentile — riskier than 79% of all scored CVEsHighest risk

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

How urgent is this, really

CVE-2021-46703 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 385,386 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

1 pkg affected

.NETRazorEngine

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

In the IsolatedRazorEngine component of Antaris RazorEngine through 4.5.1-alpha001, an attacker can execute arbitrary .NET code in a sandboxed environment (if users can externally control template contents). NOTE: This vulnerability only affects products that are no longer supported by the maintainer

Affected Packages

1 total

Ecosystem	Package	Vulnerable range	Fix
.NETNuGet	`RazorEngine`	all versions	No fix

Affected Products

1 product · 2 configurations

Application

razorenginerazorengine_project

< 4.5.1

1 version

4.5.1

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

In the IsolatedRazorEngine component of Antaris RazorEngine through 4.5.…

github.comNVDMar 2022

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for RazorEngine, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Remediation status
No patched version of RazorEngine has shipped for CVE-2021-46703 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
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.

Frequently Asked Questions

O3 Security · Impact-Aware SCA

Is CVE-2021-46703 in your dependencies?

Find it across NuGet, including transitive dependencies.

Scan my dependencies How O3 SCA works