How severe is CVE-2021-26099?

CVE-2021-26099 has a CVSS 3.x base score of 4.4, rated medium severity. It is exploitable over network with high attack complexity, requires high privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2021-26099 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (42nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-26099?

CVE-2021-26099 affects Fortinet Fortimail. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-26099?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-26099 published?

CVE-2021-26099 was published on 2021-07-12 and last updated on 2026-06-17.

CVE-2021-26099

CVE-2021-26099 is a medium-severity vulnerability in Fortinet Fortimail with a CVSS 3.x base score of 4.4. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: Medium (CVSS 3.x base score 4.4)
CVSS v2: 4.0
EPSS exploit prediction: 1% (42nd percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Fortinet Fortimail
Published: 2021-07-12
Last modified: 2026-06-17

Description

Missing cryptographic steps in the Identity-Based Encryption service of FortiMail before 7.0.0 may allow an attacker who comes in possession of the encrypted master keys to compromise their confidentiality by observing a few invariant properties of the ciphertext.

Frequently asked questions

What is CVE-2021-26099?: Missing cryptographic steps in the Identity-Based Encryption service of FortiMail before 7.0.0 may allow an attacker who comes in possession of the encrypted master keys to compromise their confidentiality by observing a few invariant properties of the ciphertext.
How severe is CVE-2021-26099?: CVE-2021-26099 has a CVSS 3.x base score of 4.4, rated medium severity. It is exploitable over network with high attack complexity, requires high privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2021-26099 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (42nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-26099?: CVE-2021-26099 affects Fortinet Fortimail. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-26099?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-26099 published?: CVE-2021-26099 was published on 2021-07-12 and last updated on 2026-06-17.

References

https://fortiguard.com/advisory/FG-IR-20-244

Affected products (1)

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

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