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FortiosOperating system · Fortinet

CVE-2025-53844

HIGH · 8.8 CVSS v3.1 Published 2026-05-12
Fix available
A fix is available. Upgrade to 7.2.12 / 7.4.9 or later.
See remediation →
94/100
Remediation priority · Urgent
Remotely reachable Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
A out-of-bounds write vulnerability in Fortinet FortiOS 7.6.0 through 7.6.3, FortiOS 7.4.0 through 7.4.8, FortiOS 7.2.0 through 7.2.11 allows attacker to execute unauthorized code or commands via specially crafted packets.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

An out-of-bounds write vulnerability in Fortinet FortiOS versions 7.6.0-7.6.3, 7.4.0-7.4.8, and 7.2.0-7.2.11 allows remote attackers to execute unauthorized code or commands via specially crafted packets. This is a memory corruption vulnerability in the system's packet processing logic that can lead to arbitrary code execution.

MitigationApply Fortinet's available patches for FortiOS to upgrade to a supported version. If immediate patching is not possible, restrict network access to the FortiOS management interfaces and disable unnecessary services to reduce the attack surface.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
FortiosOperating system
Affected:>= 7.2.0, < 7.2.12>= 7.4.0, < 7.4.9>= 7.6.0, < 7.6.4

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify FortiOS version
    Run command: get system status | grep FortiOS or execute 'diagnose system version' via CLI
    Affected if The version displayed is within any of these ranges: 7.2.0-7.2.11, 7.4.0-7.4.8, or 7.6.0-7.6.3
  2. Confirm network processing is active
    Check that the FortiOS device has network interfaces configured and operational with 'get system interface' or 'diagnose hardware devicelist'
    Affected if Network interfaces are up and processing traffic, as the vulnerability resides in packet processing within the kernel or network module
  3. Verify management access exposure
    Review current firewall policy and interface access lists with 'get system interface' and 'show firewall policy' to identify exposed management ports
    Affected if Management interfaces (HTTP/HTTPS/SSH) are accessible from untrusted networks, as remote attackers can exploit via specially crafted packets

You are affected if your FortiOS version falls within 7.2.0-7.2.11, 7.4.0-7.4.8, or 7.6.0-7.6.3 and the device processes network traffic on exposed interfaces.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 7.2.12 / 7.4.9 / 7.6.4 or later
Fixed in 7.2.127.4.97.6.4
Interim mitigation

Apply Fortinet's available patches for FortiOS to upgrade to a supported version. If immediate patching is not possible, restrict network access to the FortiOS management interfaces and disable unnecessary services to reduce the attack surface.

Recommended fix High confidence

FortiOS 7.2.12, 7.4.9, or 7.6.4 (depending on your current branch)

  1. 1. Identify the current FortiOS version by running 'get system status' or 'fortios -v' in the CLI
  2. 2. Determine the appropriate upgrade path based on your current version branch (7.2.x, 7.4.x, or 7.6.x)
  3. 3. Download the corresponding FortiOS firmware image from https://support.fortinet.com/ (requires valid support contract)
  4. 4. Review Fortinet's upgrade guide and release notes for your target version to ensure compatibility
  5. 5. Back up the current FortiOS configuration using 'execute backup config' or via FortiManager if deployed
  6. 6. Upload the new firmware image via Web UI (System > Firmware) or CLI: 'execute system firmware-upgrade'
  7. 7. Confirm the upgrade and allow the device to reboot (this may take several minutes)
  8. 8. After reboot, verify the new version with 'get system status' and confirm it matches the target fixed version (7.2.12, 7.4.9, or 7.6.4)
Caveat Review release notes for any configuration changes or deprecated features between your current and target version; some hardware models may have specific firmware limitations

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Fortios Scoped from the published advisory
  • Consultation6.0 h
  • Implementation12.0 h
  • Testing8.0 h
  • Review / QA4.0 h
30.0 hours of engineering $5,280
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2025-53844 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data