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FortiwebApplication · Fortinet

CVE-2025-48840

MEDIUM · 5.3 CVSS v3.1 Published 2026-03-10
Fix available
A fix is available. Upgrade to 7.4.9 / 7.6.4 or later.
See remediation →
62/100
Remediation priority · Elevated
Remotely reachable No privileges 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
An authentication bypass by spoofing vulnerability in Fortinet FortiWeb 7.6.0 through 7.6.3, FortiWeb 7.4.0 through 7.4.8, FortiWeb 7.2 all versions, FortiWeb 7.0 all versions may allow a remote unauthenticated attacker to bypass hostname restrictions via a specially crafted request.

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

FortiWeb web application firewall versions 7.0 through 7.6.3 contain an authentication bypass by spoofing vulnerability. Attackers can bypass hostname restrictions through specially crafted HTTP requests, potentially allowing unauthorized access to protected resources without valid credentials.

MitigationApply vendor patches for FortiWeb; until patched, implement strict Host header validation at upstream proxies or load balancers to filter malformed requests.

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
FortiwebApplication
Affected:>= 7.0.0, < 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
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
None

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

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 FortiWeb installed version
    Log into FortiWeb CLI and run the command 'get system status' or access the web UI dashboard to view the firmware version displayed under Device Information.
    Affected if The displayed version falls within 7.0.0 to 7.4.8, or 7.6.0 to 7.6.3.
  2. Confirm version is within first affected range
    Compare the major.minor.patch version number from step 1 against the range 7.0.0 (inclusive) to 7.4.8 (inclusive).
    Affected if Version is 7.0.0 through 7.4.8.
  3. Confirm version is within second affected range
    Compare the major.minor.patch version number from step 1 against the range 7.6.0 (inclusive) to 7.6.3 (inclusive).
    Affected if Version is 7.6.0 through 7.6.3.
  4. Check Host header validation configuration
    Access FortiWeb web UI or CLI to review server policy settings related to hostname validation or Host header checking. Look for settings that validate incoming Host headers against allowed hostnames.
    Affected if Host header validation is not enabled or is configured to allow arbitrary Host values.

If FortiWeb version is 7.0.0-7.4.8 or 7.6.0-7.6.3 and Host header validation is not properly enforced, the environment is vulnerable to CVE-2025-48840.

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 7.4.9 / 7.6.4 or later
Fixed in 7.4.97.6.4
Interim mitigation

Apply vendor patches for FortiWeb; until patched, implement strict Host header validation at upstream proxies or load balancers to filter malformed requests.

Recommended fix Moderate confidence

FortiWeb 7.4.9+ or 7.6.4+ (contact Fortinet for 7.0.x/7.2.x patch options)

  1. Identify the currently installed FortiWeb version using the web UI (System > Status) or CLI: 'get system status'
  2. If running 7.6.0-7.6.3, upgrade to version 7.6.4 or later
  3. If running 7.4.0-7.4.8, upgrade to version 7.4.9 or later
  4. For 7.0.x and 7.2.x branches, contact Fortinet support for patch availability or consider upgrading to a supported branch (7.4.9+ or 7.6.4+)
  5. After upgrade, verify the version change and test that hostname restriction controls function correctly
  6. Review admin profiles and hostname-based access policies to ensure they are configured as intended
Caveat Upgrading between major branches may require configuration review; test in staging first

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

Fix this in Fortiweb Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing3.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,490
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Scan for this in your stack

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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-2025-48840 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