CVE-2022-26122

An insufficient verification of data authenticity vulnerability [CWE-345] in FortiClient, FortiMail and FortiOS AV engines version 6.2.168 and below and version 6.4.274 and below may allow an attacker to bypass the AV engine via manipulating MIME attachment with junk and pad characters in base64.

Published: 2022-11-02 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2022-26122 is rated Low Risk (31.5/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.44%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2022-26122

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.10% 0.44% +0.35%
2 2025-03-30 0.17% 0.10% -0.07%
3 2025-03-29 — 0.17% —

Full EPSS history (6 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2022-26122

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
4.7 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:L/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 2.8 1.4 [email protected]
8.6 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
 3.9 4.0 [email protected]

Weakness enumeration for CVE-2022-26122

Affected software / configurations for CVE-2022-26122

Vendor Product Version Raw CPE
fortinet antivirus_engine 0.4.23 cpe:2.3:a:fortinet:antivirus_engine:0.4.23:*:*:*:*:*:*:*
fortinet antivirus_engine 2.0.49 cpe:2.3:a:fortinet:antivirus_engine:2.0.49:*:*:*:*:*:*:*
fortinet antivirus_engine 2.0.60 cpe:2.3:a:fortinet:antivirus_engine:2.0.60:*:*:*:*:*:*:*
fortinet antivirus_engine 4.4.54 cpe:2.3:a:fortinet:antivirus_engine:4.4.54:*:*:*:*:*:*:*
fortinet antivirus_engine 6.33 cpe:2.3:a:fortinet:antivirus_engine:6.33:*:*:*:*:*:*:*
fortinet antivirus_engine 6.137 cpe:2.3:a:fortinet:antivirus_engine:6.137:*:*:*:*:*:*:*
fortinet antivirus_engine 6.142 cpe:2.3:a:fortinet:antivirus_engine:6.142:*:*:*:*:*:*:*
fortinet antivirus_engine 6.144 cpe:2.3:a:fortinet:antivirus_engine:6.144:*:*:*:*:*:*:*
fortinet antivirus_engine 6.145 cpe:2.3:a:fortinet:antivirus_engine:6.145:*:*:*:*:*:*:*
fortinet antivirus_engine 6.156 cpe:2.3:a:fortinet:antivirus_engine:6.156:*:*:*:*:*:*:*
fortinet antivirus_engine 6.157 cpe:2.3:a:fortinet:antivirus_engine:6.157:*:*:*:*:*:*:*
fortinet antivirus_engine 6.243 cpe:2.3:a:fortinet:antivirus_engine:6.243:*:*:*:*:*:*:*
fortinet antivirus_engine 6.252 cpe:2.3:a:fortinet:antivirus_engine:6.252:*:*:*:*:*:*:*
fortinet antivirus_engine 6.253 cpe:2.3:a:fortinet:antivirus_engine:6.253:*:*:*:*:*:*:*
fortinet fortimail >= 6.0.0, <= 6.0.12 cpe:2.3:a:fortinet:fortimail:*:*:*:*:*:*:*:*
fortinet fortimail >= 6.2.0, <= 6.2.9 cpe:2.3:a:fortinet:fortimail:*:*:*:*:*:*:*:*
fortinet fortimail >= 6.4.0, <= 6.4.6 cpe:2.3:a:fortinet:fortimail:*:*:*:*:*:*:*:*
fortinet fortimail >= 7.0.0, <= 7.0.2 cpe:2.3:a:fortinet:fortimail:*:*:*:*:*:*:*:*
fortinet fortimail 4.1.0 cpe:2.3:a:fortinet:fortimail:4.1.0:*:*:*:*:*:*:*
fortinet fortios >= 6.0.0, <= 6.0.15 cpe:2.3:o:fortinet:fortios:*:*:*:*:*:*:*:*
fortinet fortios >= 6.2.0, <= 6.2.11 cpe:2.3:o:fortinet:fortios:*:*:*:*:*:*:*:*
fortinet fortios >= 6.4.0, <= 6.4.10 cpe:2.3:o:fortinet:fortios:*:*:*:*:*:*:*:*
fortinet fortios >= 7.0.0, <= 7.0.6 cpe:2.3:o:fortinet:fortios:*:*:*:*:*:*:*:*
fortinet fortios 7.2.0 cpe:2.3:o:fortinet:fortios:7.2.0:*:*:*:*:*:*:*

References for CVE-2022-26122

URL Tags
https://fortiguard.com/psirt/FG-IR-22-074 Patch Vendor Advisory
cvelogic Threat Intelligence