Is CVE-2026-39812 in the CISA KEV catalog?

No. CVE-2026-39812 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-39812?

CVE-2026-39812 has a CVSS v3 base score of 4.8 (MEDIUM).

What is the EPSS score for CVE-2026-39812?

CVE-2026-39812 has an EPSS score of 0.19% (9th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-39812?

Upgrade fortisandbox to 5.0.6 or later.

CVE & CISA-KEV Catalog

CVE-2026-39812

MEDIUM

4.8

CVSS v3

NVD

Description

A improper neutralization of input during web page generation ('cross-site scripting') vulnerability in Fortinet FortiSandbox 5.0.0 through 5.0.5, FortiSandbox 4.4.0 through 4.4.8, FortiSandbox 4.2 all versions, FortiSandbox PaaS 5.0.0 through 5.0.5, FortiSandbox PaaS 4.4.0 through 4.4.8, FortiSandbox PaaS 4.2 all versions may allow attacker to execute unauthorized code or commands via <insert attack vector here>

CWE-79Cross-Site Scripting (XSS)

How to fix

Remediation Available

fortisandboxNVD

Affected:>= 5.0.0, < 5.0.6Fixed in:5.0.6CVE-2026-39812derived from NVD

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredHigh

User InteractionRequired

ScopeChanged

Impact

ConfidentialityLow

IntegrityLow

AvailabilityNone

CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N

Exploit Intelligence

0.19%probability of exploitation in 30 days

9thpercentile

Low risk: more likely to be exploited than 9% of all known CVEs.

References

Vendor Advisory1

fortiguard.fortinet.com

Related Vulnerabilities

Other CWE-79 (Cross-Site Scripting (XSS)) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2020-11022	Medium	6.9	99%	-	Fix
CVE-2019-3929	Critical	9.8	99%	KEV	Fix
CVE-2020-9496	Medium	6.1	99%	-	-
CVE-2023-28341	Medium	6.1	99%	-	Fix
CVE-2018-12998	Medium	6.1	98%	-	-
CVE-2025-4123	High	7.6	98%	-	Fix

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-04-21.