Is CVE-2026-6643 in the CISA KEV catalog?

No. CVE-2026-6643 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-6643?

CVE-2026-6643 has a CVSS v3 base score of 9.9 (CRITICAL).

What is the EPSS score for CVE-2026-6643?

CVE-2026-6643 has an EPSS score of 0.47% (37th percentile), estimating the probability of exploitation in the next 30 days.

CVE & CISA-KEV Catalog

CVE-2026-6643

CRITICAL

9.9

CVSS v3

NVD

Description

A stack-based buffer overflow vulnerability was found in the VPN Clients on the ADM. The issue stems from the use of unbounded sscanf() and passing user-controlled data directly to printf(). Due to the lack of PIE and Stack Canary protections, an authenticated remote attacker can exploit these to execute arbitrary code as the web server user. Affected products and versions include: from ADM 4.1.0 through ADM 4.3.3.RR42 as well as from ADM 5.0.0 through ADM 5.1.2.REO1.

CWE-121

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredLow

User InteractionNone

ScopeChanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Exploit Intelligence

0.47%probability of exploitation in 30 days

37thpercentile

Low risk: more likely to be exploited than 37% of all known CVEs.

References

https://www.asustor.com/security/security_advisory_detail?id=54

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-04-22.