pyLoad: Unbounded Memory Growth Leading to DoS and Potential DDoS in EventManager

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

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

EPSS

• CVE-2026-48987: 0.44% estimated exploitation activity in the next 30 days; percentile 37.89 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Description: The EventManager module in pyload manages a list of Client instances for subscribing to events. The addition of each unique uuid from the getevents API causes the creation of a Client instance that gets appended to the clients list. Although there is a clean() method available in the EventManager module for removing non-responding Client instances, this method is never used in the EventManager or in the entire core application code. Consequently, this causes an uncontrolled growth in memory consumption until it becomes exhausted, resulting in a DoS attack. Vulnerable Code: https://github.com/pyload/pyload/blob/355c3f8d78a91f72d049e58f1edee8a972f845eb/src/pyload/core/managers/eventmanager.py#L16-L17 Here the client is added to the clients list but never cleared the inactive clients. Exploitation: 1. Start pyLoad server (Ensure the pyload server is running) 2. Authenticate: Obtain a session cookie or an API key (Here i used the API key). 3. Send Requests: Run the below poc…

Published by the source

9 Jul 2026, 13:35 UTC

Last modified by the source

13 Jul 2026, 16:42 UTC

Source last checked

26 Oct 2026, 13:46 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-c2f9-4mc8-j656

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-c2f9-4mc8-j656

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# Patch Next advisory brief: CVE-2026-48987

Advisory: pyLoad: Unbounded Memory Growth Leading to DoS and Potential DDoS in EventManager
IDs: CVE-2026-48987, GHSA-c2f9-4mc8-j656
Record: https://patchnext.com/advisories/cve-2026-48987 (revision 2, source checked 26 Oct 2026, 13:46 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor response not established. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI pyload-ng: affected <= 0.5.0b3.dev100

## Suggested inspection (read-only)
- `python -m pip show pyload-ng`: prints the installed version. Run with the environment that serves production active.

## Supported action
No complete vendor fix is recorded. Follow the primary source's mitigation guidance and check this record again before closing anything.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on pyload-ng.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-c2f9-4mc8-j656 (OSV record GHSA-c2f9-4mc8-j656 lists affected ranges: PyPI pyload-ng >=0 <=0.5.0b3.dev100)
- Verified: https://github.com/advisories/GHSA-c2f9-4mc8-j656 (GitHub-reviewed advisory GHSA-c2f9-4mc8-j656 lists affected ranges: PyPI pyload-ng >=0 <=0.5.0b3.dev100)

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