How severe is CVE-2021-3330?

CVE-2021-3330 has a CVSS 3.x base score of 7.1, rated high severity. It is exploitable over an adjacent network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability low.

Is CVE-2021-3330 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (44th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-3330?

CVE-2021-3330 affects Zephyrproject Zephyr. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-3330?

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-2021-3330 published?

CVE-2021-3330 was published on 2021-10-12 and last updated on 2026-06-17.

CVE-2021-3330

CVE-2021-3330 is a high-severity vulnerability in Zephyrproject Zephyr with a CVSS 3.x base score of 7.1. 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-787.

Key facts

Severity: High (CVSS 3.x base score 7.1)
CVSS v2: 5.8
EPSS exploit prediction: 1% (44th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-787
Affected product: Zephyrproject Zephyr
Published: 2021-10-12
Last modified: 2026-06-17

Description

RCE/DOS: Linked-list corruption leading to large out-of-bounds write while sorting for forged fragment list in Zephyr. Zephyr versions >= >=2.4.0 contain Out-of-bounds Write (CWE-787). For more information, see https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-fj4r-373f-9456

Frequently asked questions

What is CVE-2021-3330?: RCE/DOS: Linked-list corruption leading to large out-of-bounds write while sorting for forged fragment list in Zephyr. Zephyr versions >= >=2.4.0 contain Out-of-bounds Write (CWE-787). For more information, see https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-fj4r-373f-9456
How severe is CVE-2021-3330?: CVE-2021-3330 has a CVSS 3.x base score of 7.1, rated high severity. It is exploitable over an adjacent network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability low.
Is CVE-2021-3330 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (44th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-3330?: CVE-2021-3330 affects Zephyrproject Zephyr. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-3330?: 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-2021-3330 published?: CVE-2021-3330 was published on 2021-10-12 and last updated on 2026-06-17.

References

http://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-fj4r-373f-9456

Affected products (1)

cpe:2.3:o:zephyrproject:zephyr:*:*:*:*:*:*:*:*

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