Cross-origin access via plus-sign path normalization
Published Mar 20, 2025 · Updated Nov 3, 2025
Origin validation error in Cory Dolphin Flask-CORS 5.0.1 and earlier allows remote attackers to gain unauthorized cross-origin access. Resource matching passes request.path to unquote_plus, which converts a valid plus sign to a space before selecting the applicable CORS policy. Exposure requires a plus-sign route with resource-specific CORS rules; the mismatch can disclose responses to a disallowed origin or block an allowed origin.
Summary
What happened
Origin validation error in Cory Dolphin Flask-CORS 5.0.1 and earlier allows remote attackers to gain unauthorized cross-origin access. Resource matching passes request.path to unquote_plus, which converts a valid plus sign to a space before selecting the applicable CORS policy. Exposure requires a plus-sign route with resource-specific CORS rules; the mismatch can disclose responses to a disallowed origin or block an allowed origin.
The record
- CVE
- CVE-2024-6844
- Published
- Mar 20, 2025
- Updated
- Nov 3, 2025
- Vendor
- Cory Dolphin
- Product
- Flask-CORS
- Classifications
- CWE-346
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Mar 20, 2025CVE publishedPublication date reported by the CVE source.
- Nov 3, 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=unspecified <=latest
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
Public exploit references
- Plus-sign path CORS mismatch regression testsproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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