How severe is CVE-2021-31987?

CVE-2021-31987 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-31987 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (54th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-31987?

CVE-2021-31987 primarily affects Axis Axis Os. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-31987?

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-2021-31987 published?

CVE-2021-31987 was published on 2021-10-05 and last updated on 2026-06-17.

CVE-2021-31987

CVE-2021-31987 is a high-severity vulnerability in Axis Axis Os 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-1286.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.1
EPSS exploit prediction: 1% (54th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-1286
Affected product: Axis Axis Os
Published: 2021-10-05
Last modified: 2026-06-17

Description

A user controlled parameter related to SMTP test functionality is not correctly validated making it possible to bypass blocked network recipients.

Frequently asked questions

What is CVE-2021-31987?: A user controlled parameter related to SMTP test functionality is not correctly validated making it possible to bypass blocked network recipients.
How severe is CVE-2021-31987?: CVE-2021-31987 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-31987 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (54th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-31987?: CVE-2021-31987 primarily affects Axis Axis Os. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-31987?: 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-2021-31987 published?: CVE-2021-31987 was published on 2021-10-05 and last updated on 2026-06-17.

References

https://www.axis.com/files/tech_notes/CVE-2021-31987.pdf

Affected products (4)

cpe:2.3:o:axis:axis_os:*:*:*:*:active:*:*:*
cpe:2.3:o:axis:axis_os_2016:*:*:*:*:lts:*:*:*
cpe:2.3:o:axis:axis_os_2018:*:*:*:*:lts:*:*:*
cpe:2.3:o:axis:axis_os_2020:*:*:*:*:lts:*:*:*

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