How severe is CVE-2026-39812?

CVE-2026-39812 has a CVSS 3.x base score of 4.8, rated medium severity. It is exploitable over network with low attack complexity, requires high privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2026-39812 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (9th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-39812?

CVE-2026-39812 primarily affects Fortinet Fortisandbox. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2026-39812?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-39812 have an EU (EUVD) identifier?

Yes. CVE-2026-39812 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-22342.

When was CVE-2026-39812 published?

CVE-2026-39812 was published on 2026-04-14 and last updated on 2026-06-17.

CVE-2026-39812

CVE-2026-39812 is a medium-severity vulnerability in Fortinet Fortisandbox with a CVSS 3.x base score of 4.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-79.

Key facts

Severity: Medium (CVSS 3.x base score 4.8)
EPSS exploit prediction: 0% (9th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-22342
Weakness: CWE-79
Affected product: Fortinet Fortisandbox
Published: 2026-04-14
Last modified: 2026-06-17

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>

Frequently asked questions

What is CVE-2026-39812?: 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>
How severe is CVE-2026-39812?: CVE-2026-39812 has a CVSS 3.x base score of 4.8, rated medium severity. It is exploitable over network with low attack complexity, requires high privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2026-39812 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (9th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-39812?: CVE-2026-39812 primarily affects Fortinet Fortisandbox. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-39812?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-39812 have an EU (EUVD) identifier?: Yes. CVE-2026-39812 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-22342.
When was CVE-2026-39812 published?: CVE-2026-39812 was published on 2026-04-14 and last updated on 2026-06-17.

References

https://fortiguard.fortinet.com/psirt/FG-IR-26-110

Affected products (4)

cpe:2.3:a:fortinet:fortisandbox:*:*:*:*:*:*:*:*
cpe:2.3:a:fortinet:fortisandbox_cloud:*:*:*:*:*:*:*:*
cpe:2.3:a:fortinet:fortisandbox_cloud:5.0.4:*:*:*:*:*:*:*
cpe:2.3:a:fortinet:fortisandbox_cloud:5.0.5:*:*:*:*:*:*:*

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