FortiAuthenticator: Out-of-bounds Read
CVE-2025-53379 is a high-severity out-of-bounds read vulnerability in FortiAuthenticator from Fortinet, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected FortiAuthenticator versions: 6.6.0 through 6.6.2; 6.5.0 through 6.5.7; 6.4.0 through 6.4.11, 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 0.53% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of FortiAuthenticator 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 | FortiAuthenticator | 6.6.0 through 6.6.2; 6.5.0 through 6.5.7; 6.4.0 through 6.4.11; 6.3.0 through 6.3.5 | 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
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- NoneNothing can be modified.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N. Scored by CNA (fortinet.com).
Official description
A out-of-bounds read vulnerability in Fortinet FortiAuthenticator 6.6.0 through 6.6.2, FortiAuthenticator 6.5 all versions may allow a remote unauthenticated attacker to retrieve sensitive information via a specially crafted request.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Out-of-bounds Read
The product reads data past the end, or before the beginning, of the intended buffer.
How developers prevent this class of flaw
- Use a language that provides appropriate memory abstractions.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Other vulnerabilities in FortiAuthenticator
- 9.0 Critical severity
- 8.3 High severity
- 9.1 Critical severity
- 8.2 High severity
- 7.2 High severity
- 7.5 High severity
Recent Out-of-bounds Read vulnerabilities
- 8.6 High severity
- 7.0 High severity
- 7.0 High severity
- 7.0 High severity
- 9.1 Critical severity
- 9.1 Critical severity
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