Cross-origin policy bypass via reflected request Origin
Published Dec 11, 2023 · Updated Aug 2, 2024
Origin validation error in Koa.js @koa/cors before 5.0.0 allows remote attackers to bypass same-origin controls via a crafted Origin header. In index.js, the default origin selection substitutes the request's Origin value when options.origin is unset and returns that value in Access-Control-Allow-Origin. Exposure requires a Koa application to use the middleware without an explicit origin policy, causing browsers to accept attacker-controlled web origins as allowed.
Summary
What happened
Origin validation error in Koa.js @koa/cors before 5.0.0 allows remote attackers to bypass same-origin controls via a crafted Origin header. In index.js, the default origin selection substitutes the request's Origin value when options.origin is unset and returns that value in Access-Control-Allow-Origin. Exposure requires a Koa application to use the middleware without an explicit origin policy, causing browsers to accept attacker-controlled web origins as allowed.
The record
- CVE
- CVE-2023-49803
- Published
- Dec 11, 2023
- Updated
- Aug 2, 2024
- Vendor
- Koa.js
- Product
- @koa/cors
- Classifications
- CWE-346, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Dec 11, 2023CVE publishedPublication date reported by the CVE source.
- Aug 2, 2024Record 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=< 5.0.0
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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Public exploit references
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Technologies
Your stack
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Your stack
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