How severe is CVE-2021-43517?

CVE-2021-43517 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-2021-43517 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (74th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-43517?

CVE-2021-43517 affects Foscam Fi9805e Firmware. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-43517?

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-2021-43517 published?

CVE-2021-43517 was published on 2022-04-08 and last updated on 2026-06-17.

CVE-2021-43517

CVE-2021-43517 is a critical-severity vulnerability in Foscam Fi9805e 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.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 10.0
EPSS exploit prediction: 2% (74th percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Foscam Fi9805e Firmware
Published: 2022-04-08
Last modified: 2026-06-17

Description

FOSCAM Camera FI9805E with firmware V4.02.R12.00018510.10012.143900.00000 contains a backdoor that opens Telnet port when special command is sent on port 9530.

Frequently asked questions

What is CVE-2021-43517?: FOSCAM Camera FI9805E with firmware V4.02.R12.00018510.10012.143900.00000 contains a backdoor that opens Telnet port when special command is sent on port 9530.
How severe is CVE-2021-43517?: CVE-2021-43517 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-2021-43517 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (74th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-43517?: CVE-2021-43517 affects Foscam Fi9805e Firmware. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-43517?: 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-2021-43517 published?: CVE-2021-43517 was published on 2022-04-08 and last updated on 2026-06-17.

References

https://habr.com/ru/post/486856/

Affected products (1)

cpe:2.3:o:foscam:fi9805e_firmware:4.02.r12.00018510.10012.143900.00000:*:*:*:*:*:*:*

More vulnerabilities in Foscam Fi9805e Firmware

CVE-2018-6832 — High (CVSS 7.5): Stack-based buffer overflow in the getSWFlag function in Foscam Cameras C1 Lite V3, and C1 V3 with firmware 2.82.2.33…
CVE-2018-6830 — High (CVSS 7.5): Directory traversal vulnerability in Foscam Cameras C1 Lite V3, and C1 V3 with firmware 2.82.2.33 and earlier, FI9800P…
CVE-2018-6831 — High (CVSS 7.2): The setSystemTime function in Foscam Cameras C1 Lite V3, and C1 V3 with firmware 2.82.2.33 and earlier, FI9800P V3,…

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