High severity · published Sep 15, 2026
CVE-2026-61554
emp3r0r has an unauthenticated HTTP Polling DoS
7.5
CVSS
0.7%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.7% · higher than 53% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
EM
emp3r0r · jm33-m0
< 4.2.5 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-61554
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-61554
github.com
https://github.com/jm33-m0/emp3r0r/releases/tag/v4.2.5
github.com
https://github.com/jm33-m0/emp3r0r/security/advisories/GHSA-4595-rvpx-4q34
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