How severe is CVE-2021-40404?

CVE-2021-40404 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2021-40404 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (65th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-40404?

CVE-2021-40404 affects Reolink Rlc-410w Firmware. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-40404?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-40404 published?

CVE-2021-40404 was published on 2022-01-28 and last updated on 2026-06-17.

CVE-2021-40404

CVE-2021-40404 is a medium-severity vulnerability in Reolink Rlc-410w Firmware with a CVSS 3.x base score of 6.5. 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-287.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
CVSS v2: 6.4
EPSS exploit prediction: 1% (65th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-287
Affected product: Reolink Rlc-410w Firmware
Published: 2022-01-28
Last modified: 2026-06-17

Description

An authentication bypass vulnerability exists in the cgiserver.cgi Login functionality of reolink RLC-410W v3.0.0.136_20121102. A specially-crafted HTTP request can lead to authentication bypass. An attacker can send an HTTP request to trigger this vulnerability.

Frequently asked questions

What is CVE-2021-40404?: An authentication bypass vulnerability exists in the cgiserver.cgi Login functionality of reolink RLC-410W v3.0.0.136_20121102. A specially-crafted HTTP request can lead to authentication bypass. An attacker can send an HTTP request to trigger this vulnerability.
How severe is CVE-2021-40404?: CVE-2021-40404 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2021-40404 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (65th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-40404?: CVE-2021-40404 affects Reolink Rlc-410w Firmware. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-40404?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-40404 published?: CVE-2021-40404 was published on 2022-01-28 and last updated on 2026-06-17.

References

https://talosintelligence.com/vulnerability_reports/TALOS-2021-1420

Affected products (1)

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

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CVE-2021-40408 — Critical (CVSS 9.8): An OS command injection vulnerability exists in the device network settings functionality of reolink RLC-410W…
CVE-2021-40416 — High (CVSS 8.8): An incorrect default permission vulnerability exists in the cgiserver.cgi cgi_check_ability functionality of reolink…
CVE-2022-21796 — High (CVSS 8.2): A memory corruption vulnerability exists in the netserver parse_command_list functionality of reolink RLC-410W…
CVE-2021-44419 — High (CVSS 7.7): A denial of service vulnerability exists in the cgiserver.cgi JSON command parser functionality of reolink RLC-410W…

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Other CWE-287 (Improper Authentication) vulnerabilities

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CVE-2026-10611 — Critical (CVSS 10.0): An authentication bypass vulnerability exists in MISP when LDAP mixed authentication is enabled with OTP enforcement.…
CVE-2026-47280 — Critical (CVSS 10.0): Improper authentication in Azure Resource Manager (ARM) allows an unauthorized attacker to elevate privileges over a…
CVE-2026-42822 — Critical (CVSS 10.0): Improper authentication in Azure Local Disconnected Operations allows an unauthorized attacker to elevate privileges…
CVE-2026-20182 — Critical (CVSS 10.0): May 2026: This security advisory provides the details and fix information for a vulnerability that was discovered and…

Browse all CWE-287 (Improper Authentication) vulnerabilities →