What is CVE-2026-8398?

CVE-2026-8398 is a critical-severity vulnerability in Avb Disc Soft Daemon Tools Lite, classified under CWE-506. CVSS score: 9.8/10. Published 2026-05-15.

How severe is CVE-2026-8398?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Is CVE-2026-8398 known to be exploited?

Yes. CVE-2026-8398 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2026-05-27), indicating it is being actively exploited.

Vulnerability in Avb Disc Soft Daemon Tools Lite

CVE-2026-8398

A supply chain attack compromised the official installation packages of DAEMON Tools Lite (Windows versions 12.5.0.2421 through 12.5.0.2434), distributed from the legitimate website daemon-tools.cc between approximately April 8, 2026, and May 5, 2026. Attackers gained unauthorized access to the vendor's (AVB Disc Soft) build or distribution infrastructure and trojanized three binaries: DTHelper.exe, DiscSoftBusServiceLite.exe, and DTShellHlp.exe. These files were digitally signed with the legitimate AVB Disc Soft code-signing certificate, allowing the malicious installers to appear trustworthy and bypass signature-based detection.

Published 2026-05-15 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.010 (61.0th percentile), scored 2026-10-19.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 61st percentile — 61.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.015 · newest: 0.010 · change: -0.005

Affected products

Avb Disc Soft Daemon Tools Lite — versions 12.5.0.2421
Disc-Soft Daemon Tools — versions 12.5.1
Microsoft Windows

Weakness classification (CWE)

CWE-506

CISA KEV (Known Exploited Vulnerabilities)

This CVE is on the CISA KEV catalog, added on 2026-05-27. CISA KEV inclusion means CISA has confirmed in-the-wild exploitation; US federal agencies are required to remediate within a published due date.

BOD 22-01 due date: 2026-05-30.

Required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

References

securelist.com/tr/daemon-tools-backdoor/119654/ (Exploit, technical-description, Third Party Advisory, third-party-advisory)
blog.daemon-tools.cc/post/security-incident (vendor-advisory, Vendor Advisory)
134c704f-9b21-4f2e-91b3-4a467353bcc0 (US Government Resource)

Frequently asked questions

What is CVE-2026-8398?: CVE-2026-8398 is a critical-severity vulnerability in Avb Disc Soft Daemon Tools Lite, classified under CWE-506. CVSS score: 9.8/10. Published 2026-05-15.
How severe is CVE-2026-8398?: Critical severity. CVSS v3 base score is 9.8 out of 10.
Is CVE-2026-8398 known to be exploited?: Yes. CVE-2026-8398 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2026-05-27), indicating it is being actively exploited.