What is CVE-2021-26095?

CVE-2021-26095 is a high-severity vulnerability in Fortinet Fortimail. CVSS score: 7.5/10. Published 2021-07-20.

How severe is CVE-2021-26095?

High severity. CVSS v3 base score is 7.5 out of 10.

Vulnerability in Fortinet Fortimail

CVE-2021-26095

The combination of various cryptographic issues in the session management of FortiMail 6.4.0 through 6.4.4 and 6.2.0 through 6.2.6, including the encryption construction of the session cookie, may allow a remote attacker already in possession of a cookie to possibly reveal and alter or forge its content, thereby escalating privileges.

Published 2021-07-20 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.007 (52.0th percentile), scored 2026-10-20.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 52nd percentile — 52.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.007 · newest: 0.007 · change: 0.000

Affected products

Fortinet Fortimail
Fortinet Fortimail — versions FortiMail 6.4.0 through 6.4.4 and 6.2.0 through 6.2.6

References

fortiguard.com/advisory/FG-IR-21-019 (Vendor Advisory)

Frequently asked questions

What is CVE-2021-26095?: CVE-2021-26095 is a high-severity vulnerability in Fortinet Fortimail. CVSS score: 7.5/10. Published 2021-07-20.
How severe is CVE-2021-26095?: High severity. CVSS v3 base score is 7.5 out of 10.