File-filter bypass via crafted HTTP headers
Published Jan 14, 2025 · Updated Aug 6, 2025
HTTP response splitting in Fortinet FortiOS and FortiProxy allows remote attackers to bypass explicit-web-proxy file filtering. The explicit web proxy file filter fails to neutralize CRLF sequences in attacker-controlled HTTP headers, allowing a crafted header to split the response and evade the filtering decision. Exploitation requires network access to an affected explicit web proxy; the bounded result is passage of content that the configured file filter should block.
Summary
What happened
HTTP response splitting in Fortinet FortiOS and FortiProxy allows remote attackers to bypass explicit-web-proxy file filtering. The explicit web proxy file filter fails to neutralize CRLF sequences in attacker-controlled HTTP headers, allowing a crafted header to split the response and evade the filtering decision. Exploitation requires network access to an affected explicit web proxy; the bounded result is passage of content that the configured file filter should block.
The record
- CVE
- CVE-2024-54021
- Published
- Jan 14, 2025
- Updated
- Aug 6, 2025
- Vendor
- Fortinet
- Product
- FortiOS
- Classifications
- CWE-113
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jan 14, 2025CVE publishedPublication date reported by the CVE source.
- Aug 6, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
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- Affected versionversion=7.2.0 <=7.2.8
- Affected versionversion=7.4.0 <=7.4.4
- Affected versionversion=7.6.0
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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