CVE-2026-59840 Information disclosure in FortiOS

What is CVE-2026-59840?

CVE-2026-59840 is a medium-severity vulnerability in Fortinet Fortios, published on 14 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.

Official description

A buffer over-read vulnerability in Fortinet FortiOS 7.6.0 through 7.6.3, FortiOS 7.4.0 through 7.4.8, FortiOS 7.2 all versions, FortiOS 7.0 all versions, FortiOS 6.4 all versions, FortiProxy 7.6.0 through 7.6.5, FortiProxy 7.4.0 through 7.4.13, FortiProxy 7.2 all versions, FortiProxy 7.0 all versions may allow attacker to information disclosure via <insert attack vector here>

Weakness: CWE-126

Which versions are affected by CVE-2026-59840?

It affects 2 products.

Products include Fortinet Fortios, Fortinet Fortiproxy.

How do I fix CVE-2026-59840?

No fix has been published for CVE-2026-59840 yet. Limit exposure of the affected software until one is available.

Is CVE-2026-59840 being exploited?

There is no known exploitation of CVE-2026-59840 in the wild and no public exploit code.

Other vulnerabilities in Fortinet Fortios

• CVE-2024-23113 Fortinet Multiple Products Format String Exploited Critical 9.8
• CVE-2022-40684 Fortinet Multiple Products Authentication Bypass Exploited Critical 9.8
• CVE-2024-55591 Fortinet FortiOS and FortiProxy Authentication Bypass Exploited Critical 9.6
• CVE-2024-21762 Fortinet FortiOS Out-of-Bound Write Exploited Critical 9.6
• CVE-2022-42475 Fortinet FortiOS Heap-Based Buffer Overflow Exploited Critical 9.3

All Fortinet Fortios vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-r538-x648-7vg8.