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CVE-2026-39813 is a critical path traversal vulnerability in the JRPC API of Fortinet FortiSandbox. The flaw affects FortiSandbox 4.4.0 through 4.4.8 and 5.0.0 through 5.0.5. By sending specially crafted HTTP requests containing traversal sequences to the JRPC API, a remote attacker can bypass intended access controls and authentication checks. Multiple reports also characterize the issue as enabling privilege escalation through the API after authentication is bypassed. The vulnerability is pre-authentication and network exploitable.
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1 valid exploit after Mallory filtered fakes, detection scripts, and README-only repos (2 hidden).
This repository is a small exploit repo with 3 files: a Python PoC, a Nuclei template, and a README. Because it includes a Nuclei template, it is part of a framework; the main exploit logic is captured in CVE-2026-39808.yaml, while the Python script provides a standalone implementation of the same attack chain. The exploit targets Fortinet FortiSandbox and chains an unauthenticated access check against /api/v1/system/firmware (described as CVE-2026-39813 auth bypass) with a command injection in /fortisandbox/job-detail/tracer-behavior via the jid parameter (CVE-2026-39808). The injected command writes output to /web/ng/out.txt, which is then retrieved from /ng/out.txt to confirm root-level execution. The Nuclei template fingerprints the login page, extracts version information, triggers a benign id payload, and verifies success by matching uid=0/gid=0 in the output. Overall, this is a real unauthenticated web RCE PoC for vulnerable FortiSandbox versions, providing root command execution and simple output exfiltration through a web-accessible file.
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85 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
A Fortinet FortiSandbox vulnerability mentioned as being observed under exploitation alongside the primary flaws, but not the main focus of the article.
Another FortiSandbox vulnerability mentioned as being targeted alongside the primary FortiSandbox flaws, but not otherwise described in detail.
An authentication bypass vulnerability in the FortiSandbox API that allows attackers to bypass login controls and gain access to administrative functions.
A critical path-traversal vulnerability in Fortinet FortiSandbox that researchers observed being exploited.
Query your assets running an affected version, and investigate the blast radius.
Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
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Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.