CVE-2026-27848

CriticalRCE

Published: 25 February 2026

Published

25 February 2026

Modified

15 April 2026

KEV Added

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Patch

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CVSS Score v3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Score 0.0032 23.6th percentile

Risk Priority 70 floored blend · peak EPSS

Summary

CVE-2026-27848 is a critical-severity OS Command Injection (CWE-78) vulnerability in Syss (inferred from references). Its CVSS base score is 9.8 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 23.6th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified are NIST 800-53 SI-10 (Information Input Validation) and SI-2 (Flaw Remediation).

Deeper analysis

CVE-2026-27848 is a critical vulnerability (CVSS 9.8, CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H) involving OS command injection (CWE-78) due to missing neutralization of special elements in the TLS-SRP handshake of affected devices. This flaw allows injected OS commands to be executed with root privileges. The issue impacts MR9600 firmware version 1.0.4.205530 and MX4200 firmware version 1.0.13.210200.

Attackers can exploit this vulnerability remotely over the network without authentication, privileges, or user interaction, requiring only low complexity. Successful exploitation enables arbitrary OS command execution as the root user, resulting in high-impact compromise of confidentiality, integrity, and availability, such as full control over the device.

Mitigation guidance is provided in the SYSS advisory at https://www.syss.de/fileadmin/dokumente/Publikationen/Advisories/SYSS-2025-010.txt, published ahead of the CVE disclosure on 2026-02-25.

OWASP Top 10 for Web (2025)

EU & UK References

🇪🇺 ENISA EUVD: EUVD-2026-8650

Vulnerability details

Due to missing neutralization of special elements, OS commands can be injected via the handshake of a TLS-SRP connection, which are ultimately run as the root user. This issue affects MR9600: 1.0.4.205530; MX4200: 1.0.13.210200.

CWE(s): CWE-78

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access

Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.

attack.mitre.org →

T1059.004 Unix Shell Execution

Adversaries may abuse Unix shell commands and scripts for execution.

attack.mitre.org →

Why these techniques?

Remote unauthenticated OS command injection (CWE-78) in exposed TLS-SRP service directly enables initial access via public-facing application exploitation (T1190) and arbitrary root-level command execution via Unix shell (T1059.004).

Confidence: HIGH · MITRE ATT&CK Enterprise v19.0