Unauthenticated Authentication bypass and Privilege escalation in FortiSandbox

unknownCVE-2026-39813

CVSSv3 Score: 9.1 A Path Traversal vulnerability [CWE-24] in FortiSandbox JRPC API may allow an unauthenticated attacker to bypass authentication via specially crafted HTTP requests. Revised on 2026-04-14 00:00:00

CSIRTS triage

vendor: Fortinet product: FortiSandbox Authentication bypass Privilege escalation

What: An unauthenticated attacker can bypass authentication and escalate privileges via crafted HTTP requests.
Who is affected: Deployments of FortiSandbox.
Urgency: This critical vulnerability requires immediate remediation to prevent unauthorized access and privilege escalation.
Action: Update FortiSandbox to the latest version to mitigate this vulnerability.

AI-assisted analysis generated from the source advisory — verify against the original.

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Details

Source: Fortinet FortiGuard PSIRT (INTL · vendor-psirt · site)
Severity: unknown
Published: 2026-04-14
Exploitation: Not in CISA KEV at last sync

Original advisory: https://fortiguard.fortinet.com/psirt/FG-IR-26-112

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Elevated exploitation riskCVE-2026-3981316.7% 30-day exploitation probability — well above the norm. Schedule remediation this cycle. Riskier than 97% of all scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-39813	coverage & exploitation status	NVD · CVE.org

Recent advisories for Unauthenticated Authentication bypass

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

criticalCVE-2026-58122: Hermes WebUI before 0.51.307 contains an authentication bypass vulnerability that allows unaut…nvd · 2026-07-09
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criticalCVE-2026-5268: An authentication bypass vulnerability exists in the default SFTP server component utilized acr…nvd · 2026-07-06
mediumCVE-2026-35159: Dell Client Platform BIOS contains an Authentication Bypass by Primary Weakness vulnerability.…nvd · 2026-07-03
highCVE-2026-59092: JuiceFS through 1.3.1, fixed in commit a46979c, contains an authentication bypass vulnerabilit…nvd · 2026-07-02
unknownCVE-2026-58399: @acastellon/auth is an authentication control system for microservices. Versions prior to 2.3.…nvd · 2026-07-01