Fortinet AV Engine, FortiMail, FortiOS…: Insufficient Verification of Data Authenticity
CVE-2022-26122 is a high-severity insufficient verification of data authenticity vulnerability in Fortinet AV Engine, FortiMail, FortiOS, FortiClient from Fortinet, with a CVSS 3.1 base score of 8.6 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. There is no confirmed exploitation so far. EPSS estimates a 0.63% chance of exploitation within 30 days, higher than 51% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of Fortinet AV Engine, FortiMail, FortiOS, FortiClient you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on fortiguard.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Fortinet | Fortinet AV Engine, FortiMail, FortiOS, FortiClient | Not specified in the record | Not stated |
| Fortinet | Antivirus Engine | 0.4.23; 2.0.49; 2.0.60; 4.4.54; 6.33; 6.137; 6.142; 6.144; and 6 more ranges | Not stated |
| Fortinet | Fortimail | 6.0.0 through 6.0.12; 6.2.0 through 6.2.9; 6.4.0 through 6.4.6; 7.0.0 through 7.0.2; 4.1.0 | Not stated |
| Fortinet | Fortios | 6.0.0 through 6.0.15; 6.2.0 through 6.2.11; 6.4.0 through 6.4.10; 7.0.0 through 7.0.6; 7.2.0 | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- ChangedThe attack can reach beyond the vulnerable component into other systems.
- Confidentiality
- NoneNo data is disclosed.
- Integrity
- HighData or code can be modified at will.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 4.7 | Medium | CNA (fortinet.com) |
| CVSS 3.1 | 8.6 | High | NVD |
Official description
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.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Insufficient Verification of Data Authenticity
The product does not sufficiently verify the origin or authenticity of data, in a way that causes it to accept invalid data.
More Insufficient Verification of Data Authenticity vulnerabilities (CWE-345)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Recent Insufficient Verification of Data Authenticity vulnerabilities
- 7.5 High severity
- 9.9 Critical severity
- 8.8 High severity
- 7.5 High severity
- 7.8 High severity
- 7.8 High severity
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