Security-policy bypass via discarded duplicate headers
Published Feb 1, 2024 · Updated Jun 17, 2025
Response-header interpretation conflict in Bref before 2.1.13 allows remote attackers to weaken browser security policies via API Gateway v2. HttpResponse::toApiGatewayFormatV2 replaces an array of same-name header values with only its last element instead of preserving every value. Exposure requires an HTTP API deployment whose PHP response relies on repeated security headers; discarded CSP directives permit otherwise-blocked script execution.
Summary
What happened
Response-header interpretation conflict in Bref before 2.1.13 allows remote attackers to weaken browser security policies via API Gateway v2. HttpResponse::toApiGatewayFormatV2 replaces an array of same-name header values with only its last element instead of preserving every value. Exposure requires an HTTP API deployment whose PHP response relies on repeated security headers; discarded CSP directives permit otherwise-blocked script execution.
The record
- CVE
- CVE-2024-24753
- Published
- Feb 1, 2024
- Updated
- Jun 17, 2025
- Vendor
- Bref
- Product
- Bref
- Classifications
- Unavailable
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Feb 1, 2024CVE publishedPublication date reported by the CVE source.
- Jun 17, 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?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 2.1.13
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
No sourced classifications are available.
Public exploit references
- Upstream API Gateway v2 repeated-header proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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