Trapster Community: Unauthenticated malformed DNS compression pointers crash per-packet honeypot handler

Exploitation

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

CVSS

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

EPSS

No dated EPSS signal available.

As published by the source; long descriptions are shortened.

Summary trapster.libs.dns.decodelabels() decodes DNS names from attacker-supplied UDP packets and recurses once per RFC 1035 compression pointer with no cycle detection and no depth bound. A single unauthenticated UDP datagram sent to the DNS honeypot drives the function past CPython's recursion limit, raising RecursionError. That exception is not handled anywhere on the datagramreceived path, so it escapes into the asyncio event loop's default exception handler, the per-packet proxy task is never created, and a low-rate flood produces sustained CPU burn and log flooding (denial of service of the DNS honeypot module). Severity Medium (CVSS:3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L). Network-reachable, unauthenticated, single-packet, availability-only against the DNS honeypot listener. Affected component - File: trapster/libs/dns.py, function decodelabels() (called by decodequestionsection → decodednsmessage). - Reached from: trapster/modules/dns.py, DnsUdpProtocol.datagramreceived() →…

Published by the source

8 Jul 2026, 20:24 UTC

Last modified by the source

8 Jul 2026, 20:30 UTC

Source last checked

26 Oct 2026, 13:46 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-mxwc-wh95-pw4g

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-mxwc-wh95-pw4g

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# Patch Next advisory brief: GHSA-mxwc-wh95-pw4g

Advisory: Trapster Community: Unauthenticated malformed DNS compression pointers crash per-packet honeypot handler
IDs: GHSA-mxwc-wh95-pw4g
Record: https://patchnext.com/advisories/ghsa-mxwc-wh95-pw4g (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 5.3)
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 trapster: affected <= 1.2.0

## Suggested inspection (read-only)
- `python -m pip show trapster`: 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 trapster.
- 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-mxwc-wh95-pw4g (OSV record GHSA-mxwc-wh95-pw4g lists affected ranges: PyPI trapster >=0 <=1.2.0)
- Verified: https://github.com/advisories/GHSA-mxwc-wh95-pw4g (GitHub-reviewed advisory GHSA-mxwc-wh95-pw4g lists affected ranges: PyPI trapster >=0 <=1.2.0)

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