9.9

CVE-2026-6643: asustor inc. adm Stack-based Buffer Overflow

CVSS: 9.9v3.1CriticalAnalyzed
Published 20-04-2026Last modified 20-04-2026
Open JSON

Vulnerability summary

CVE-2026-6643 is a critical (CVSS 9.9) Stack-based Buffer Overflow vulnerability in asustor inc. adm. EPSS estimates a 0.76% chance of exploitation in the next 30 days, higher than 54.6% of scored vulnerabilities.

Overall risk
70/100
0100
High · default modelHow is this calculated?
CVSS score
9.9/10
010
Critical · v3.1 (NVD)
EPSS score
0.76%
0%100%
Low · +0.30 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 20-04-2026
    PublishedVulnerability first disclosed.
  2. 20-04-2026
    Last modifiedVulnerability information updated.

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.

CVSS metrics

3 scores · 2 sources · 2 versions

EPSS trend

Probability

0.76%

Chance of exploitation in the next 30 days

Percentile

55%

Versus all other CVEs

30-day change

+0.30 pp

From 0.47% on 20-09-2026

20-09-202620-10-2026
EPSS score
0.76%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Asustor1 product
  • data_master≥ 4.1.0.rhu2, < 4.3.3.RR42 | ≥ 5.0.0.ra82, < 5.1.2.reo1
Asustor inc.1 product
  • adm≥ 4.1.0, ≤ 4.3.3.RR42 | ≥ 5.0.0, ≤ 5.1.2.REO1

2 vendors · 2 products

References

1 links