FortiOS: Path Traversal: '../filedir'
CVE-2026-126255 is a high-severity path traversal: '../filedir' vulnerability in FortiOS from Fortinet, with a CVSS 3.1 base score of 7.4 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected FortiOS versions: 8.0.0 through 8.0.1; 7.6.0 through 7.6.7; 7.4.0 through 7.4.12, and others listed below. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.75% chance of exploitation within 30 days, higher than 56% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of FortiOS you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on fortiguard.fortinet.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 | FortiOS | 8.0.0 through 8.0.1; 7.6.0 through 7.6.7; 7.4.0 through 7.4.12; 7.2.0 through 7.2.13 | Not stated |
| Fortinet | FortiPAM | 1.6.0 through 1.6.2; 1.5.0 through 1.5.1; 1.4.0 through 1.4.3; 1.3.0 through 1.3.1; 1.2.0; 1.1.0 through 1.1.2; 1.0.0 through 1.0.3 | 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
- HighSuccess depends on conditions outside the attacker's control.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N. Scored by CNA (fortinet.com).
Official description
A path traversal: '../filedir' vulnerability in Fortinet FortiOS 8.0.0 through 8.0.1, FortiOS 7.6.0 through 7.6.7, FortiOS 7.4.0 through 7.4.12, FortiOS 7.2.0 through 7.2.13, FortiPAM 1.6 all versions, FortiPAM 1.5 all versions, FortiPAM 1.4 all versions, FortiPAM 1.3 all versions, FortiPAM 1.2 all versions, FortiPAM 1.1 all versions, FortiPAM 1.0 all versions may allow an unauthenticated attacker to bypass authentication via specially crafted credentials.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Path Traversal: '../filedir'
The product uses external input to construct a pathname that should be within a restricted directory, but it does not properly neutralize../ sequences that can resolve to a location that is outside of that directory.
How developers prevent this class of flaw
- Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174). Such errors could be used to bypass allowlist validation schemes by introducing dangerous inputs after they have been checked.
Timeline
- CVE record published.
- Record last changed materially (score, affected products, status or references).
References
Other vulnerabilities in FortiOS
- 9.8 Critical severity
- 7.5 High severity
- 7.4 High severity
- 9.6 Critical severity
- 9.3 Critical severity
- 8.1 High severity
Recent Path Traversal: '../filedir' vulnerabilities
- 8.1 High severity
- 8.8 High severity
- 7.1 High severity
- 7.5 High severity
- 7.5 High severity
- 8.5 High severity
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