How severe is CVE-2023-33966?

CVE-2023-33966 has a CVSS score of 8.6/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2023-33966?

CVE-2023-33966 affects the following packages: deno (crates.io), deno_runtime (crates.io). Ecosystems affected: crates.io.

How do I fix CVE-2023-33966?

Update deno to 1.34.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-33966 is resolved across your whole dependency graph.

How do I detect CVE-2023-33966 in my crates.io dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for deno. 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-2023-33966 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-2023-33966?

O3 pinpoints whether CVE-2023-33966 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-2023-33966 actively exploited in the wild?

No public exploit code has been indexed for CVE-2023-33966 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-2023-33966?

CVE-2023-33966 has an EPSS (Exploit Prediction Scoring System) score of 0.6%, placing it in the 45th 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-2023-33966 published, and has it been updated?

CVE-2023-33966 was published on May 31, 2023 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.

🦀 crates.io

CVE-2023-33966

HIGH

Deno missing "--allow-net" permission check for built-in Node modules

Also known asGHSA-vc52-gwm3-8v2f

Published

May 31, 2023

Updated

Apr 10, 2026

Affected

2 pkgs

Patched

2 / 2

Exploits

None indexed

EPSS Exploitation Probability

via FIRST.org ↗

0.6%probability of exploitation in next 30 days

Lower Risk45th percentile+0.31%

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

2 pkgs affected

🦀deno🦀deno_runtime

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

Description

Deno is a runtime for JavaScript and TypeScript. In deno 1.34.0 and deno_runtime 0.114.0, outbound HTTP requests made using the built-in node:http or node:https modules are incorrectly not checked against the network permission allow list (--allow-net). Dependencies relying on these built-in modules are subject to the vulnerability too. Users of Deno versions prior to 1.34.0 are unaffected. Deno Deploy users are unaffected. This problem has been patched in Deno v1.34.1 and deno_runtime 0.114.1 and all users are recommended to update to this version. No workaround is available for this issue.

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
🦀crates.io	`deno`	≥ 1.34.0&&< 1.34.1	1.34.1
🦀crates.io	`deno_runtime`	≥ 0.114.0&&< 0.115.0	0.115.0

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for deno. 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 deno to 1.34.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-33966 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-2023-33966 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-2023-33966. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

Deno is a runtime for JavaScript and TypeScript. In deno 1.34.0 and deno_runtime 0.114.0, outbound HTTP requests made using the built-in `node:http` or `node:https` modules are incorrectly not checked against the network permission allow list (`--allow-net`). Dependencies relying on these built-in modules are subject to the vulnerability too. Users of Deno versions prior to 1.34.0 are unaffected. Deno Deploy users are unaffected. This problem has been patched in Deno v1.34.1 and deno_runtime 0.114.1 and all users are recommended to update to this version. No workaround is available for this is

O3 Security · Impact-Aware SCA

Is CVE-2023-33966 in your dependencies?

O3 detects CVE-2023-33966 across crates.io 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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