Deno is vulnerable to race condition via interactive permission prompt spoofingGHSA-mc52-jpm2-cqh6
HIGHFix: denoland/deno#17392GHSA-mc52-jpm2-cqh6 is a high-severity (CVSS 8.8) CWE-362 vulnerability in deno. 1 public exploit or proof-of-concept reference is indexed, so weaponization risk is real. A fix is available for deno — see the affected versions and patch details below.
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 GHSA-mc52-jpm2-cqh6.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
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
Impact
Multi-threaded programs were able to spoof interactive permission prompt by rewriting the prompt to suggest that program is waiting on user confirmation to unrelated action.
A malicious program could clear the terminal screen after permission prompt was shown and write a generic message like so:
// Expected prompt
⚠️ ┌ Deno requests read access to "./log.txt".
├ Requested by `Deno.open()` API
├ Run again with --allow-read to bypass this prompt.
└ Allow? [y/n] (y = yes, allow; n = no, deny) >
// Prompt that users would see
Do you want to continue?
This situation impacts users who use Web Worker API and relied on interactive permission prompt. The reproduction is very timing sensitive and can’t be reliably reproduced on every try.
This problem can not be exploited on systems that do not attach an interactive prompt (for example headless servers).
Patches
The problem has been fixed in Deno v1.29.3; it is recommended all users update to this version.
Workarounds
Run with --no-prompt flag to disable interactive permission prompts.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | deno | ≥ 1.9.0&&< 1.29.3 | 1.29.3cargo update -p deno --precise 1.29.3 |
Affected Products
denodenoResearch 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, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update deno to 1.29.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-mc52-jpm2-cqh6 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.
Frequently Asked Questions
Is GHSA-mc52-jpm2-cqh6 in your dependencies?
Find it across crates.io, including transitive dependencies.