How severe is CVE-2021-3661?

CVE-2021-3661 has a CVSS 3.x base score of 8.4, rated high severity. It is exploitable over local access with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-3661 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (22nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-3661?

CVE-2021-3661 primarily affects Hp Z1 All-in-one G3 Firmware. In total, 20 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-3661?

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-2021-3661 published?

CVE-2021-3661 was published on 2022-12-12 and last updated on 2026-06-17.

CVE-2021-3661

CVE-2021-3661 is a high-severity vulnerability in Hp Z1 All-in-one G3 Firmware with a CVSS 3.x base score of 8.4. 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-94.

Key facts

Severity: High (CVSS 3.x base score 8.4)
EPSS exploit prediction: 0% (22nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-94
Affected product: Hp Z1 All-in-one G3 Firmware
Published: 2022-12-12
Last modified: 2026-06-17

Description

A potential security vulnerability has been identified in certain HP Workstation BIOS (UEFI firmware) which may allow arbitrary code execution. HP is releasing firmware mitigations for the potential vulnerability.

Frequently asked questions

What is CVE-2021-3661?: A potential security vulnerability has been identified in certain HP Workstation BIOS (UEFI firmware) which may allow arbitrary code execution. HP is releasing firmware mitigations for the potential vulnerability.
How severe is CVE-2021-3661?: CVE-2021-3661 has a CVSS 3.x base score of 8.4, rated high severity. It is exploitable over local access with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-3661 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (22nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-3661?: CVE-2021-3661 primarily affects Hp Z1 All-in-one G3 Firmware. In total, 20 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-3661?: 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-2021-3661 published?: CVE-2021-3661 was published on 2022-12-12 and last updated on 2026-06-17.

References

https://support.hp.com/us-en/document/ish_5670997-5671021-16/hpsbhf03770

Affected products (20)

cpe:2.3:o:hp:z1_all-in-one_g3_firmware:01.31:*:*:*:*:*:*:*
cpe:2.3:o:hp:z2_mini_g3_firmware:01.83:*:*:*:*:*:*:*
cpe:2.3:o:hp:z2_mini_g4_firmware:01.08.01:*:*:*:*:*:*:*
cpe:2.3:o:hp:z2_mini_g5_firmware:01.03.00_rev_a:*:*:*:*:*:*:*
cpe:2.3:o:hp:z2_small_form_factor_g4_firmware:01.08.01:*:*:*:*:*:*:*
cpe:2.3:o:hp:z2_small_form_factor_g5_firmware:01.03.00_rev_a:*:*:*:*:*:*:*
cpe:2.3:o:hp:z2_small_form_factor_g8_firmware:01.03.00_rev_a:*:*:*:*:*:*:*
cpe:2.3:o:hp:z2_tower_g4_firmware:01.08.01:*:*:*:*:*:*:*
cpe:2.3:o:hp:z2_tower_g5_firmware:01.03.00_rev_a:*:*:*:*:*:*:*
cpe:2.3:o:hp:z2_tower_g8_firmware:01.03.00_rev_a:*:*:*:*:*:*:*
cpe:2.3:o:hp:z238_microtower_firmware:01.83:*:*:*:*:*:*:*
cpe:2.3:o:hp:z240_small_form_factor_firmware:01.83:*:*:*:*:*:*:*
cpe:2.3:o:hp:z240_tower_firmware:01.83:*:*:*:*:*:*:*
cpe:2.3:o:hp:z4_g4_firmware:02.75:*:*:*:*:*:*:*
cpe:2.3:o:hp:z440_firmware:2.58:*:*:*:*:*:*:*
cpe:2.3:o:hp:z6_g4_firmware:02.75:*:*:*:*:*:*:*
cpe:2.3:o:hp:z640_firmware:2.58:*:*:*:*:*:*:*
cpe:2.3:o:hp:z8_g4_firmware:02.75:*:*:*:*:*:*:*
cpe:2.3:o:hp:z840_firmware:2.58:*:*:*:*:*:*:*
cpe:2.3:o:hp:zcentral_4r_firmware:01.18:*:*:*:*:*:*:*

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