Cross-origin data exposure via regex rule misordering
Published Mar 20, 2025 · Updated Nov 3, 2025
Improper path matching in Cory Dolphin Flask-CORS 5.0.1 and earlier allows remote attackers to read sensitive data via cross-origin requests. The parse_resources function uses a flawed specificity sort, so a broad resource regex can precede a narrower endpoint rule and apply its permissive CORS policy. Exploitation requires overlapping resource patterns with different policies and user interaction with an attacker-controlled origin; the bounded impact is unauthorized response disclosure.
Summary
What happened
Improper path matching in Cory Dolphin Flask-CORS 5.0.1 and earlier allows remote attackers to read sensitive data via cross-origin requests. The parse_resources function uses a flawed specificity sort, so a broad resource regex can precede a narrower endpoint rule and apply its permissive CORS policy. Exploitation requires overlapping resource patterns with different policies and user interaction with an attacker-controlled origin; the bounded impact is unauthorized response disclosure.
The record
- CVE
- CVE-2024-6839
- Published
- Mar 20, 2025
- Updated
- Nov 3, 2025
- Vendor
- Cory Dolphin
- Product
- Flask-CORS
- Classifications
- CWE-41, T1189
- 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?
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.
Public exploit references
- Huntr vulnerability reportproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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