Is CVE-2026-8406 in the CISA KEV catalog?

No. CVE-2026-8406 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-8406?

CVE-2026-8406 has a CVSS v4 base score of 7.1 (HIGH).

What is the EPSS score for CVE-2026-8406?

CVE-2026-8406 has an EPSS score of 0.24% (15th percentile), estimating the probability of exploitation in the next 30 days.

CVE & CISA-KEV Catalog

CVE-2026-8406

HIGH

7.1

CVSS v4

NVD

Description

openSIS Classic 9.3 contains an insecure direct object reference vulnerability in the messaging module. Any authenticated user with access to the messaging module can request sent-message details from modules/messaging/SentMail.php by supplying an arbitrary mail_id value.

CWE-639

CVSS v4 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredLow

User InteractionNone

Impact

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Exploit Intelligence

0.24%probability of exploitation in 30 days

15thpercentile

Low risk: more likely to be exploited than 15% of all known CVEs.

References

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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 2026-06-17.