How severe is CVE-2026-39811?

CVE-2026-39811 has a CVSS 3.x base score of 4.9, rated medium severity. It is exploitable over network with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2026-39811 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (29th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-39811?

CVE-2026-39811 affects Fortinet Fortiweb. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-39811?

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

Does CVE-2026-39811 have an EU (EUVD) identifier?

Yes. CVE-2026-39811 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-22340.

When was CVE-2026-39811 published?

CVE-2026-39811 was published on 2026-04-14 and last updated on 2026-06-17.

CVE-2026-39811

CVE-2026-39811 is a medium-severity vulnerability in Fortinet Fortiweb with a CVSS 3.x base score of 4.9. 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-190.

Key facts

Severity: Medium (CVSS 3.x base score 4.9)
EPSS exploit prediction: 0% (29th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-22340
Weakness: CWE-190
Affected product: Fortinet Fortiweb
Published: 2026-04-14
Last modified: 2026-06-17

Description

A integer overflow or wraparound vulnerability in Fortinet FortiWeb 8.0.0 through 8.0.3, FortiWeb 7.6.0 through 7.6.6, FortiWeb 7.4 all versions, FortiWeb 7.2 all versions, FortiWeb 7.0 all versions may allow attacker to denial of service via <insert attack vector here>

Frequently asked questions

What is CVE-2026-39811?: A integer overflow or wraparound vulnerability in Fortinet FortiWeb 8.0.0 through 8.0.3, FortiWeb 7.6.0 through 7.6.6, FortiWeb 7.4 all versions, FortiWeb 7.2 all versions, FortiWeb 7.0 all versions may allow attacker to denial of service via <insert attack vector here>
How severe is CVE-2026-39811?: CVE-2026-39811 has a CVSS 3.x base score of 4.9, rated medium severity. It is exploitable over network with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-39811 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (29th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-39811?: CVE-2026-39811 affects Fortinet Fortiweb. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-39811?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-39811 have an EU (EUVD) identifier?: Yes. CVE-2026-39811 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-22340.
When was CVE-2026-39811 published?: CVE-2026-39811 was published on 2026-04-14 and last updated on 2026-06-17.

References

https://fortiguard.fortinet.com/psirt/FG-IR-26-108

Affected products (1)

cpe:2.3:a:fortinet:fortiweb:*:*:*:*:*:*:*:*

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