How severe is CVE-2021-22129?

CVE-2021-22129 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-22129 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (62nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-22129?

CVE-2021-22129 affects Fortinet Fortimail. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-22129?

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-2021-22129 published?

CVE-2021-22129 was published on 2021-07-09 and last updated on 2026-06-17.

CVE-2021-22129

CVE-2021-22129 is a high-severity vulnerability in Fortinet Fortimail with a CVSS 3.x base score of 8.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-120.

Key facts

Severity: High (CVSS 3.x base score 8.8)
CVSS v2: 6.5
EPSS exploit prediction: 1% (62nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-120
Affected product: Fortinet Fortimail
Published: 2021-07-09
Last modified: 2026-06-17

Description

Multiple instances of incorrect calculation of buffer size in the Webmail and Administrative interface of FortiMail before 6.4.5 may allow an authenticated attacker with regular webmail access to trigger a buffer overflow and to possibly execute unauthorized code or commands via specifically crafted HTTP requests.

Frequently asked questions

What is CVE-2021-22129?: Multiple instances of incorrect calculation of buffer size in the Webmail and Administrative interface of FortiMail before 6.4.5 may allow an authenticated attacker with regular webmail access to trigger a buffer overflow and to possibly execute unauthorized code or commands via specifically crafted HTTP requests.
How severe is CVE-2021-22129?: CVE-2021-22129 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-22129 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (62nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-22129?: CVE-2021-22129 affects Fortinet Fortimail. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-22129?: 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-2021-22129 published?: CVE-2021-22129 was published on 2021-07-09 and last updated on 2026-06-17.

References

https://fortiguard.com/advisory/FG-IR-21-023

Affected products (1)

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

More vulnerabilities in Fortinet Fortimail

CVE-2025-32756 — Critical (CVSS 9.8): A stack-based buffer overflow vulnerability [CWE-121] vulnerability in Fortinet FortiCamera 2.1.0 through 2.1.3,…
CVE-2023-47539 — Critical (CVSS 9.8): An improper access control vulnerability in FortiMail version 7.4.0 configured with RADIUS authentication and…
CVE-2021-36166 — Critical (CVSS 9.8): An improper authentication vulnerability in FortiMail before 7.0.1 may allow a remote attacker to efficiently guess one…
CVE-2021-24007 — Critical (CVSS 9.8): Multiple improper neutralization of special elements of SQL commands vulnerabilities in FortiMail before 6.4.4 may…
CVE-2020-9294 — Critical (CVSS 9.8): An improper authentication vulnerability in FortiMail 5.4.10, 6.0.7, 6.2.2 and earlier and FortiVoiceEntreprise 6.0.0…
CVE-2023-36556 — High (CVSS 8.8): An incorrect authorization vulnerability [CWE-863] in FortiMail webmail version 7.2.0 through 7.2.2, version 7.0.0…

All CVEs affecting Fortinet Fortimail →

Other CWE-120 (Classic Buffer Overflow) vulnerabilities

CVE-2025-48611 — Critical (CVSS 10.0): In DeviceId of DeviceId.java, there is a possible desync in persistence due to a missing bounds check. This could lead…
CVE-2026-24823 — Critical (CVSS 10.0): Out-of-bounds Write, Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') vulnerability in FASTSHIFT…
CVE-2026-24810 — Critical (CVSS 10.0): Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') vulnerability in rethinkdb (src/cjson modules).…
CVE-2026-24800 — Critical (CVSS 10.0): Out-of-bounds Write, Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') vulnerability in tildearrow…
CVE-2025-9962 — Critical (CVSS 10.0): A buffer overflow vulnerability in Novakon P series allows attackers to gain root permission without prior…
CVE-2010-10016 — Critical (CVSS 10.0): BS.Player version 2.57 (build 1051) contains a vulnerability in its playlist import functionality. When processing .m3u…

Browse all CWE-120 (Classic Buffer Overflow) vulnerabilities →