CVE-2026-45306 pyload CVE debrief

Who should care

Organizations running pyLoad download manager instances, particularly those with multi-user deployments or exposed administrative interfaces. Security teams should prioritize patching due to the account takeover impact, though exploitation requires authenticated high-privilege access which may limit exposure in properly segmented environments.

Technical summary

This vulnerability represents a partial fix bypass in pyLoad's storage_folder validation logic. The application prevents setting storage_folder to the package directory (PKGDIR) or user directory (userdir), but omits protection for the Flask session directory at /tmp/pyLoad/flask. An attacker with authenticated high-privilege access can manipulate the storage_folder configuration to point to this session directory, then use the /files/get/ endpoint to download session files belonging to other users. Successful exploitation enables session hijacking and complete account takeover of other user accounts. The CVSS 3.1 vector CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N indicates network attack vector, low complexity, high privileges required, no user interaction, unchanged scope, with high impact to confidentiality and integrity but no availability impact.

Defensive priority

HIGH

Recommended defensive actions

• Upgrade pyLoad to version 0.5.0b3.dev100 or later to remediate this vulnerability
• Review and restrict administrative access to pyLoad instances to reduce attack surface
• Monitor for unauthorized access attempts to the /files/get/ endpoint
• Audit file system permissions on /tmp/pyLoad/flask to ensure proper isolation
• Verify that storage_folder configuration cannot be manipulated to point to sensitive system directories

Evidence notes

The CVE description indicates this is a bypass of a prior fix for CVE-2026-33509. The original fix restricted storage_folder from being set to PKGDIR or userdir, but failed to include the Flask session directory (/tmp/pyLoad/flask) in these restrictions. An authenticated attacker with high privileges can exploit this path validation gap to access session files belonging to other users.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.