CVE-2026-61554

HIGHCVSS 7.5/10EPSS 0.55%

Last modified

CVE-2026-61554 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. 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. EPSS estimates a 0.55% chance of exploitation in the next 30 days.

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.

Metrics

EPSS Probability
0.55%

44.6th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
jm33-m0emp3r0r< 4.2.5

References

Timeline

Published
Last Modified
Status
Received

Frequently Asked Questions

What is CVE-2026-61554?
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.
How severe is CVE-2026-61554?
CVE-2026-61554 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 0.55% probability of exploitation in the next 30 days.
How do I fix CVE-2026-61554?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST