How severe is CVE-2021-26111?

CVE-2021-26111 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over an adjacent network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2021-26111 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (32nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-26111?

CVE-2021-26111 affects Fortinet Fortiswitch. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-26111?

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

When was CVE-2021-26111 published?

CVE-2021-26111 was published on 2021-06-01 and last updated on 2026-06-17.

CVE-2021-26111

CVE-2021-26111 is a medium-severity vulnerability in Fortinet Fortiswitch with a CVSS 3.x base score of 6.5. 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-401.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
CVSS v2: 3.3
EPSS exploit prediction: 0% (32nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-401
Affected product: Fortinet Fortiswitch
Published: 2021-06-01
Last modified: 2026-06-17

Description

A missing release of memory after effective lifetime vulnerability in FortiSwitch 6.4.0 to 6.4.6, 6.2.0 to 6.2.6, 6.0.0 to 6.0.6, 3.6.11 and below may allow an attacker on an adjacent network to exhaust available memory by sending specifically crafted LLDP/CDP/EDP packets to the device.

Frequently asked questions

What is CVE-2021-26111?: A missing release of memory after effective lifetime vulnerability in FortiSwitch 6.4.0 to 6.4.6, 6.2.0 to 6.2.6, 6.0.0 to 6.0.6, 3.6.11 and below may allow an attacker on an adjacent network to exhaust available memory by sending specifically crafted LLDP/CDP/EDP packets to the device.
How severe is CVE-2021-26111?: CVE-2021-26111 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over an adjacent network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2021-26111 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (32nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-26111?: CVE-2021-26111 affects Fortinet Fortiswitch. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-26111?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-26111 published?: CVE-2021-26111 was published on 2021-06-01 and last updated on 2026-06-17.

References

https://fortiguard.com/advisory/FG-IR-21-026

Affected products (1)

cpe:2.3:o:fortinet:fortiswitch:*:*:*:*:*:*:*:*

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