How severe is CVE-2021-40408?

CVE-2021-40408 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-40408 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (88th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-40408?

CVE-2021-40408 affects Reolink Rlc-410w Firmware. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-40408?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2021-40408 published?

CVE-2021-40408 was published on 2022-01-28 and last updated on 2026-06-17.

CVE-2021-40408

CVE-2021-40408 is a critical-severity vulnerability in Reolink Rlc-410w Firmware with a CVSS 3.x base score of 9.8. 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-78.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 4% (88th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-78
Affected product: Reolink Rlc-410w Firmware
Published: 2022-01-28
Last modified: 2026-06-17

Description

An OS command injection vulnerability exists in the device network settings functionality of reolink RLC-410W v3.0.0.136_20121102. At [1] or [2], based on DDNS type, the ddns->username variable, that has the value of the userName parameter provided through the SetDdns API, is not validated properly. This would lead to an OS command injection.

Frequently asked questions

What is CVE-2021-40408?: An OS command injection vulnerability exists in the device network settings functionality of reolink RLC-410W v3.0.0.136_20121102. At [1] or [2], based on DDNS type, the ddns->username variable, that has the value of the userName parameter provided through the SetDdns API, is not validated properly. This would lead to an OS command injection.
How severe is CVE-2021-40408?: CVE-2021-40408 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-40408 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (88th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-40408?: CVE-2021-40408 affects Reolink Rlc-410w Firmware. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-40408?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2021-40408 published?: CVE-2021-40408 was published on 2022-01-28 and last updated on 2026-06-17.

References

https://talosintelligence.com/vulnerability_reports/TALOS-2021-1424

Affected products (1)

cpe:2.3:o:reolink:rlc-410w_firmware:3.0.0.136_20121102:*:*:*:*:*:*:*

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