high CVSS 8.1

CVE-2026-42315·Python vulnerability

pyLoad is a free and open-source download manager written in Python. Prior to 0.5.0b3.dev100, 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. This vulnerability is fixed in 0.5.0b3.dev100.

Severity
high
Software
Python
Fixed in
0.5.0b3.dev100
Published
2026-05-11

Affected versions

Until: 0.5.0b3.dev100

Fixed in: 0.5.0b3.dev100

How to fix this CVE

Update pyLoad to version 0.5.0b3.dev100 or later to patch an arbitrary directory traversal vulnerability in the set_package_data() API function. Users with MODIFY permissions could previously specify unauthorized download locations by manipulating the _folder parameter without validation. Apply this update immediately to prevent privilege escalation and unauthorized file writes on affected systems.

sudo dnf update python3-pyload

Defensia detects this vulnerability

WAF mitigation (if patching is not yet possible)

Add this rule to your WAF to block exploitation attempts while you schedule the patch. 

Implement API-level access controls restricting set_package_data() calls to trusted administrative users only; monitor for JSON payloads containing '_folder' keys with path traversal sequences (../, ..\, absolute paths); log all package configuration changes with full parameter values for audit trails.

How to check if you are affected

  1. Step 1: Check installed pyLoad version by running: python3 -m pip show pyload | grep Version
  2. Step 2: Verify the API endpoint is accessible: curl -s http://localhost:8000/api/status (default port may vary)
  3. Step 3: Search application logs for set_package_data calls with _folder parameters: grep -r '_folder' /var/log/pyload/ /var/log/pyload-api/ 2>/dev/null | grep -i set_package
  4. Step 4: Confirm the fix by re-running pip show and verifying version is 0.5.0b3.dev100 or higher

FAQ

What is CVE-2026-42315?

CVE-2026-42315 is a path traversal vulnerability in pyLoad's set_package_data() API function that allows authenticated users with MODIFY permissions to specify arbitrary filesystem directories as download destinations, bypassing intended access controls.

Is CVE-2026-42315 being actively exploited?

No, CVE-2026-42315 is not currently listed on the CISA KEV catalog and no public exploits are available, though the vulnerability remains dangerous for multi-user deployments.

What versions of pyLoad are affected by CVE-2026-42315?

All versions of pyLoad prior to 0.5.0b3.dev100 are vulnerable; the vulnerability was introduced in an unknown earlier version and patched in the specified dev release.

How do I check if my server is vulnerable to CVE-2026-42315?

Run: python3 -m pip show pyload | grep Version; if the version is lower than 0.5.0b3.dev100, your installation is vulnerable.

Does Defensia detect CVE-2026-42315?

Yes — Defensia's CVE advisory scanner compares installed package versions against the NVD database. If pyLoad is installed on a monitored server, CVE-2026-42315 will appear in your dashboard with remediation steps.

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References

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