CVE-2026-59840
CVE-2026-59840 key facts
- CISA KEV
- Not listed (catalogue checked )
- Highest advisory rating
- Medium
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N/E:P/RL:O/RC:C· base score 4.1, scored by fortinetAttack vector: network. Attack complexity: low. Privileges required: low. User interaction: none. Scope: unchanged. Confidentiality impact: low. Integrity impact: none. Availability impact: none.- Weakness
- CWE-126 Information disclosure
- EPSS
- 0.31% chance of exploitation in the next 30 days (24th percentile). FIRST EPSS, .
- CISA SSVC
- Exploitation: none observed. Automatable: no. Technical impact: partial. CISA, .
- Vendor advisories
- 1 from Fortinet
- Assigned by
- fortinet (CNA)
- CVE record published
- Listed by VulniPulse
Ratings, versions and fixes are quoted from the vendor advisories that cover only CVE-2026-59840; each belongs to its advisory, not to every product listed. How records are collected and checked.
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>
Text from the CVE.org record (fortinet).
How do I fix CVE-2026-59840?
- Upgrade to FortiOS version 7.6.4 or above Upgrade to FortiOS version 7.4.9 or above Fortinet remediated this issue in FortiSASE version 25.4.b and hence customers do not need to perform any action. Upgrade to FortiProxy version 7.6.6 or above Upgrade to FortiProxy version 7.4.14 or above (CVE.org record)
Vendor advisories for CVE-2026-59840
Fortinet
1 advisory- Advisory severityMedium4.3
Medium [CVE-2025-43892 +1] Buffer overread in authd and wad daemon
FG-IR-26-154Source published Source updated
This bulletin covers 2 CVEs. The products, versions, score and guidance below describe the bulletin; check its source for applicability to this specific CVE.
CVSSv3 Score: 4.3 A buffer over-read vulnerability [CWE-126] in FortiOS, FortiProxy, and FortiSASE may allow an authenticated remote attacker to return a portion of device memory in the redirect response via submitting a specially crafted request. Revised on 2026-07-14 00:00:00
- Affected products in this advisory
- FortiOS
- FortiProxy
- Source-reported affected versions
- FortiOS: 6.4.0 through 7.6.3 (vendor-listed versions)
- FortiProxy: 7.0.0 through 7.6.5 (vendor-listed versions)
- Source-reported fixed versions
- FortiOS 7.6: 7.6.4
- FortiOS 7.4: 7.4.9
- FortiOS 7.2: migrate to a fixed release
- FortiOS 7.0: migrate to a fixed release
5 more entries in the full advisory.
- Mitigation guidance
- Upgrade per the Affected/Solution table: FortiOS 7.6: 7.6.4; FortiOS 7.4: 7.4.9; FortiOS 7.2: migrate to a fixed release; FortiOS 7.0: migrate to a fixed release; FortiOS 6.4: migrate to a fixed release; ….
References
Timeline
- CVE record published
- First vendor advisory listed by VulniPulse
- CVE record last updated
More Fortinet advisories
CVE-2026-106175Oct 13, 2026Double free in signal handlerCVE-2025-61624Apr 14, 2026Path Traversal in CLICVE-2026-24858Jan 27, 2026FortiOS: Authentication Bypass Using an Alternate Path or Channel vulnerability [CWE-288]CVE-2025-59718Dec 9, 2025improper verification of cryptographic signature vulnerability in Fortinet FortiOS 7.6.0CVE-2025-59719Dec 9, 2025FortiOS: improper verification of cryptographic signature vulnerability in FortinetCVE-2024-47569Oct 14, 2025insertion of sensitive information into sent data vulnerability in Fortinet FortiMail
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