How severe is CVE-2021-27169?

CVE-2021-27169 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-2021-27169 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 20% (97th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-27169?

CVE-2021-27169 affects Fiberhome An5506-04-fa Firmware. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-27169?

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-2021-27169 published?

CVE-2021-27169 was published on 2021-02-10 and last updated on 2026-06-17.

CVE-2021-27169

CVE-2021-27169 is a critical-severity vulnerability in Fiberhome An5506-04-fa Firmware with a CVSS 3.x base score of 9.8. Its EPSS exploit-prediction score of 20% places it in the 97th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-798.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 5.0
EPSS exploit prediction: 20% (97th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-798
Affected product: Fiberhome An5506-04-fa Firmware
Published: 2021-02-10
Last modified: 2026-06-17

Description

An issue was discovered on FiberHome AN5506-04-FA devices with firmware RP2631. There is a gepon password for the gepon account.

Frequently asked questions

What is CVE-2021-27169?: An issue was discovered on FiberHome AN5506-04-FA devices with firmware RP2631. There is a gepon password for the gepon account.
How severe is CVE-2021-27169?: CVE-2021-27169 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-2021-27169 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 20% (97th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-27169?: CVE-2021-27169 affects Fiberhome An5506-04-fa Firmware. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-27169?: 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-2021-27169 published?: CVE-2021-27169 was published on 2021-02-10 and last updated on 2026-06-17.

References

https://pierrekim.github.io/blog/2021-01-12-fiberhome-ont-0day-vulnerabilities.html#telnet-linux-hardcoded-credentials

Affected products (1)

cpe:2.3:o:fiberhome:an5506-04-fa_firmware:rp2631:*:*:*:*:*:*:*

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