CVE-2021-31987

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.9% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-10-05 · updated 2026-06-17
Weakness: CWE-1286

Description

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

Affected products

Axis Communications AB AXIS OS: before 10.8 — fixed in 10.8
Axis Os 2016: before 6.50.5.5 — fixed in 6.50.5.5
Axis Os 2018: before 8.40.4.3 — fixed in 8.40.4.3
Axis Os 2020: before 9.80.3.5 — fixed in 9.80.3.5

How to fix

Upgrade to a fixed version: Axis Communications AB AXIS OS 10.8; Axis Os 2016 6.50.5.5; Axis Os 2018 8.40.4.3; Axis Os 2020 9.80.3.5. Check the vendor advisory for mitigations.

References

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

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