CVE-2026-29778: Pyload ng Path Traversal Vulnerability

HIGH
Advisory Identifier: GHSA-6px9-j4qr-xfjw
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CVSS 7.1
CWE-23
Published
Advisory Summary

CVE-2026-29778 is a HIGH (CVSS 7.1) path traversal vulnerability (CWE-23: Relative Path Traversal) affecting Pyload ng libraries in the PyPI ecosystem. The issue involves pyload has an arbitrary file write via path traversal in edit_package(). Remediation is available by upgrading affected packages to version 0.5.0b3.dev97.

CVE-2026-29778 at a Glance

CVE Identifier CVE-2026-29778
GHSA Identifier GHSA-6px9-j4qr-xfjw
Severity HIGH
CVSS v3.1 Base Score 7.1
CWE Classification CWE-23: Relative Path Traversal
Affected Product Pyload ng
Package Ecosystem PyPI
Published Date
Last Updated

Security Impact

CVSS: 7.1

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:L).

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 Low (A:L)

How to Fix CVE-2026-29778

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.dev97 
pip install pyload-ng>=0.5.0b3.dev97
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-2026-29778, 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.dev97), 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-23: Relative 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 sequences such as ".." 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

The edit_package() function implements insufficient sanitization for the pack_folder parameter. The current protection relies on a single-pass string replacement of "../", which can be bypassed using crafted recursive traversal sequences. Exploitation An authenticated user with MODIFY permission can bypass the sanitization by submitting a payload such as: `pack_folder=..././..././..././tmp` After the single-pass replacement, this becomes: `../../../tmp` Because the traversal sequences are not properly validated, the resulting normalized path escapes the intended storage directory and writes files to /tmp or other locations.

CVE-2026-29778 Affected Pyload ng Versions

1 component(s)
Fixed Versions:
0.5.0b3.dev97
Product / Package Ecosystem Affected Versions Fixed Version
pyload-ng
pypi/pyload-ng
PyPI
≥ 0.5.0b3.dev13
< 0.5.0b3.dev97
0.5.0b3.dev97

References

GitHub Advisory / Wiki ADVISORY
https://github.com/pyload/pyload/security/advisories/GHSA-6px9-j4qr-xfjw
NVD — CVE-2026-29778 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-29778
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-2026-121.yaml

Frequently Asked Questions

What is CVE-2026-29778?
CVE-2026-29778 is a security vulnerability in Pyload ng involving pyLoad has an Arbitrary File Write via Path Traversal in edit_package() under CWE-23: Relative Path Traversal.
Which Pyload ng versions are affected?
Affected versions include releases prior to 0.5.0b3.dev97 across affected packages: pyload-ng.
What version fixes CVE-2026-29778?
Upgrading to 0.5.0b3.dev97 (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.dev97. Upgrade your dependency to 0.5.0b3.dev97 or later.
What is the CVSS score of CVE-2026-29778?
CVE-2026-29778 has a CVSS v3.1 base score of 7.1 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:L.
What CWE is associated with CVE-2026-29778?
CVE-2026-29778 is classified under CWE-23: Relative Path Traversal (The product uses external input to construct a pathname that should be within a restricted directory, but it does not properly neutralize sequences such as ".." that can resolve to a location that is outside of that directory.).
How can I check PyPI dependencies for CVE-2026-29778?
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-6px9-j4qr-xfjw",
  "modified" : "2026-06-08T19:06:27Z",
  "published" : "2026-03-05T00:32:19Z",
  "aliases" : [ "CVE-2026-29778" ],
  "summary" : "pyLoad has an Arbitrary File Write via Path Traversal in edit_package()",
  "details" : "The edit_package() function implements insufficient sanitization for the pack_folder parameter. The current protection relies on a single-pass string replacement of \"../\", which can be bypassed using crafted recursive traversal sequences.\n\nExploitation\n\nAn authenticated user with MODIFY permission can bypass the sanitization by submitting a payload such as:\n`pack_folder=..././..././..././tmp`\n\nAfter the single-pass replacement, this becomes:\n`../../../tmp`\n\nBecause the traversal sequences are not properly validated, the resulting normalized path escapes the intended storage directory and writes files to /tmp or other locations.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:L"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "pyload-ng"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0.5.0b3.dev13"
      }, {
        "fixed" : "0.5.0b3.dev97"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 0.5.0b3.dev96"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/pyload/pyload/security/advisories/GHSA-6px9-j4qr-xfjw"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-29778"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/pyload/pyload"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/pypa/advisory-database/tree/main/vulns/pyload-ng/PYSEC-2026-121.yaml"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-23" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-03-05T00:32:19Z",
    "nvd_published_at" : "2026-03-07T16:15:54Z"
  }
}