How severe is CVE-2025-53843?

CVE-2025-53843 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with high attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2025-53843 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (43rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-53843?

CVE-2025-53843 affects Fortinet Fortios. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2025-53843?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2025-53843 have an EU (EUVD) identifier?

Yes. CVE-2025-53843 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-198006.

When was CVE-2025-53843 published?

CVE-2025-53843 was published on 2025-11-18 and last updated on 2026-06-17.

CVE-2025-53843

CVE-2025-53843 is a high-severity vulnerability in Fortinet Fortios with a CVSS 3.x base score of 7.5. 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-121.

Key facts

Severity: High (CVSS 3.x base score 7.5)
EPSS exploit prediction: 1% (43rd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-198006
Weakness: CWE-121
Affected product: Fortinet Fortios
Published: 2025-11-18
Last modified: 2026-06-17

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

Frequently asked questions

What is CVE-2025-53843?: 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
How severe is CVE-2025-53843?: CVE-2025-53843 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with high attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2025-53843 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (43rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-53843?: CVE-2025-53843 affects Fortinet Fortios. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2025-53843?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2025-53843 have an EU (EUVD) identifier?: Yes. CVE-2025-53843 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-198006.
When was CVE-2025-53843 published?: CVE-2025-53843 was published on 2025-11-18 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:o:fortinet:fortios:*:*:*:*:*:*:*:*

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