How severe is CVE-2021-26095?

CVE-2021-26095 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with high attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-26095 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (48th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-26095?

CVE-2021-26095 affects Fortinet Fortimail. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-26095?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-26095 published?

CVE-2021-26095 was published on 2021-07-20 and last updated on 2026-06-17.

CVE-2021-26095

CVE-2021-26095 is a high-severity vulnerability in Fortinet Fortimail with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 6.5
EPSS exploit prediction: 1% (48th percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Fortinet Fortimail
Published: 2021-07-20
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is 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.
How severe is CVE-2021-26095?: CVE-2021-26095 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with high attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-26095 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (48th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-26095?: CVE-2021-26095 affects Fortinet Fortimail. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-26095?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-26095 published?: CVE-2021-26095 was published on 2021-07-20 and last updated on 2026-06-17.

References

https://fortiguard.com/advisory/FG-IR-21-019

Affected products (1)

cpe:2.3:a:fortinet:fortimail:*:*:*:*:*:*:*:*

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