How severe is CVE-2021-38386?

CVE-2021-38386 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2021-38386 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (67th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-38386?

CVE-2021-38386 affects Contiki-os Contiki. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-38386?

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.

When was CVE-2021-38386 published?

CVE-2021-38386 was published on 2021-08-10 and last updated on 2026-06-17.

CVE-2021-38386

CVE-2021-38386 is a high-severity vulnerability in Contiki-os Contiki 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-120.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 1% (67th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-120
Affected product: Contiki-os Contiki
Published: 2021-08-10
Last modified: 2026-06-17

Description

In Contiki 3.0, a buffer overflow in the Telnet service allows remote attackers to cause a denial of service because the ls command is mishandled when a directory has many files with long names.

Frequently asked questions

What is CVE-2021-38386?: In Contiki 3.0, a buffer overflow in the Telnet service allows remote attackers to cause a denial of service because the ls command is mishandled when a directory has many files with long names.
How severe is CVE-2021-38386?: CVE-2021-38386 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2021-38386 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (67th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-38386?: CVE-2021-38386 affects Contiki-os Contiki. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-38386?: 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.
When was CVE-2021-38386 published?: CVE-2021-38386 was published on 2021-08-10 and last updated on 2026-06-17.

References

https://github.com/contiki-os/contiki/issues/2687

Affected products (1)

cpe:2.3:o:contiki-os:contiki:3.0:*:*:*:*:*:*:*

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