How severe is CVE-2021-27140?

CVE-2021-27140 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2021-27140 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 19% (97th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-27140?

CVE-2021-27140 affects Fiberhome Hg6245d Firmware. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-27140?

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

When was CVE-2021-27140 published?

CVE-2021-27140 was published on 2021-02-10 and last updated on 2026-06-17.

CVE-2021-27140

CVE-2021-27140 is a high-severity vulnerability in Fiberhome Hg6245d Firmware with a CVSS 3.x base score of 7.5. Its EPSS exploit-prediction score of 19% places it in the 97th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-312.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 19% (97th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-312
Affected product: Fiberhome Hg6245d Firmware
Published: 2021-02-10
Last modified: 2026-06-17

Description

An issue was discovered on FiberHome HG6245D devices through RP2613. It is possible to find passwords and authentication cookies stored in cleartext in the web.log HTTP logs.

Frequently asked questions

What is CVE-2021-27140?: An issue was discovered on FiberHome HG6245D devices through RP2613. It is possible to find passwords and authentication cookies stored in cleartext in the web.log HTTP logs.
How severe is CVE-2021-27140?: CVE-2021-27140 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2021-27140 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 19% (97th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-27140?: CVE-2021-27140 affects Fiberhome Hg6245d Firmware. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-27140?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-27140 published?: CVE-2021-27140 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#httpd-passwords-logs

Affected products (1)

cpe:2.3:o:fiberhome:hg6245d_firmware:*:*:*:*:*:*:*:*

More vulnerabilities in Fiberhome Hg6245d Firmware

CVE-2021-27177 — Critical (CVSS 9.8): An issue was discovered on FiberHome HG6245D devices through RP2613. It is possible to bypass authentication by sending…
CVE-2021-27172 — Critical (CVSS 9.8): An issue was discovered on FiberHome HG6245D devices through RP2613. A hardcoded GEPON password for root is defined…
CVE-2021-27171 — Critical (CVSS 9.8): An issue was discovered on FiberHome HG6245D devices through RP2613. It is possible to start a Linux telnetd as root on…
CVE-2021-27170 — Critical (CVSS 9.8): An issue was discovered on FiberHome HG6245D devices through RP2613. By default, there are no firewall rules for IPv6…
CVE-2021-27168 — Critical (CVSS 9.8): An issue was discovered on FiberHome HG6245D devices through RP2613. There is a 6GFJdY4aAuUKJjdtSn7d password for the…
CVE-2021-27167 — Critical (CVSS 9.8): An issue was discovered on FiberHome HG6245D devices through RP2613. There is a password of four hexadecimal characters…

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