WAF bypass via duplicate Content-Type headers
Published Jul 13, 2023 · Updated Oct 30, 2024
Type confusion in OWASP Core Rule Set 3.3.4 and earlier allows remote attackers to bypass WAF inspection via duplicate Content-Type headers. The request-header validation rules fail to reject repeated Content-Type fields, so a backend honoring only the final field can parse a body differently from the WAF. Exploitation requires a platform such as Nginx that preserves duplicate fields and a backend whose parsing choice exposes an otherwise blocked payload.
Summary
What happened
Type confusion in OWASP Core Rule Set 3.3.4 and earlier allows remote attackers to bypass WAF inspection via duplicate Content-Type headers. The request-header validation rules fail to reject repeated Content-Type fields, so a backend honoring only the final field can parse a body differently from the WAF. Exploitation requires a platform such as Nginx that preserves duplicate fields and a backend whose parsing choice exposes an otherwise blocked payload.
The record
- CVE
- CVE-2023-38199
- Published
- Jul 13, 2023
- Updated
- Oct 30, 2024
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-843, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 13, 2023CVE publishedPublication date reported by the CVE source.
- Oct 30, 2024Record updatedLatest update available in the CVE record.
Exploitability
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What is affected?
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Published CVSS scores
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Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
- Multiple Content-Type request testproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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