CVE-2026-106173 Deep-Dive: FortiSIEM gRPC Path Traversal File Write RCE
MentionsFortinet
Horizon3 researchers analyze CVE-2026-106173, a critical Fortinet FortiSIEM vulnerability affecting an unauthenticated gRPC service. The deep-dive explains how path traversal and null-byte handling enable arbitrary file writes and remote code execution, along with indicators of compromise for defenders.
Summary from Horizon3.ai.
Explained
The technology and terms in this story. Learn more
- WeaknessPath traversalUsing ../ tricks in a file name to read or write files outside the intended folder.
- AttackRemote code execution · RCEA flaw that lets an attacker run their own code on someone else's machine over the network.
- ConceptCVE · Common Vulnerabilities and ExposuresThe public ID system for vulnerabilities, such as CVE-2026-12345, so everyone means the same bug.
Why it was possible
The weaknesses behind this story's CVEs, from each CVE Record.
Vulnerabilities in this story
Severity and exploitation facts from NVD, FIRST, and CISA.