CVE-2025-53843: stack-based buffer overflow vulnerability in Fortinet FortiOS 7.6.0 through 7.6.3, FortiOS 7.4.0 through 7.4.8, FortiOS 7.2
This Fortinet advisory covers CVE-2025-53843 in FortiOS.
- CVE-2025-53843
Key facts
- Vendor rating
- High, CVSS 7.5
- CISA KEV
- Not listed (catalogue checked )
- Affected
- FortiOS: 6.4.0 through 7.6.3 (vendor-listed versions)
- Fixed in
- FortiOS 7.6: 7.6.4, FortiOS 7.4: 7.4.9, FortiOS 7.2: migrate to a fixed release and 2 more below
- Source published
- Source revised
- Listed by VulniPulse
Compiled by VulniPulse from the linked sources. How records are collected and checked.
Affected products & platforms
Description
A stack-based buffer overflow 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 allows attacker to execute unauthorized code or commands via specially crafted packets
Text from the source record.
- FortiOS: 6.4.0 through 7.6.3 (vendor-listed versions)
Official advisory · high-confidence parse· fetched ·verify at source
How to fix CVE-2025-53843
Upgrade to a fixed release named by Fortinet:
- 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
Vendor 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.
Workarounds
- Warning :if auto-auth-extension-device is enable in config system interface, any devicecan be authorized and then the vulnerability can be exploited without administratorauthorization.Please note that auto-auth-extension-device is disabled by default
Support dates for the fixed release lines
- Fortinet FortiOS 7.6: support ends
- Fortinet FortiOS 7.4: support ends
- Fortinet FortiOS 7.2: support ended
- Fortinet FortiOS 7.0: support ended
- Fortinet FortiOS 6.4: support ended
More Fortinet advisories
CVE-2026-106174Oct 13, 2026GUI Denial of ServiceCVE-2026-106175Oct 13, 2026Double free in signal handlerCVE-2025-53844May 12, 2026Out-of-bounds access in CAPWAP daemonCVE-2025-61624Apr 14, 2026Path Traversal in CLICVE-2025-68686Feb 10, 2026FortiOS information disclosureCVE-2026-22153Feb 10, 2026LDAP authentication bypass in Agentless VPN and FSSO
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