How severe is CVE-2021-27963?

CVE-2021-27963 has a CVSS 3.x base score of 8.2, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity high, and availability none.

Is CVE-2021-27963 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (82nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-27963?

CVE-2021-27963 affects Sfcyazilim Sonlogger. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-27963?

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-2021-27963 published?

CVE-2021-27963 was published on 2021-03-05 and last updated on 2026-06-17.

CVE-2021-27963

CVE-2021-27963 is a high-severity vulnerability in Sfcyazilim Sonlogger with a CVSS 3.x base score of 8.2. 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-306.

Key facts

Severity: High (CVSS 3.x base score 8.2)
CVSS v2: 6.4
EPSS exploit prediction: 2% (82nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-306
Affected product: Sfcyazilim Sonlogger
Published: 2021-03-05
Last modified: 2026-06-17

Description

SonLogger before 6.4.1 is affected by user creation with any user permissions profile (e.g., SuperAdmin). An anonymous user can send a POST request to /User/saveUser without any authentication or session header.

Frequently asked questions

What is CVE-2021-27963?: SonLogger before 6.4.1 is affected by user creation with any user permissions profile (e.g., SuperAdmin). An anonymous user can send a POST request to /User/saveUser without any authentication or session header.
How severe is CVE-2021-27963?: CVE-2021-27963 has a CVSS 3.x base score of 8.2, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity high, and availability none.
Is CVE-2021-27963 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (82nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-27963?: CVE-2021-27963 affects Sfcyazilim Sonlogger. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-27963?: 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-2021-27963 published?: CVE-2021-27963 was published on 2021-03-05 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:sfcyazilim:sonlogger:*:*:*:*:*:*:*:*

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