CVE-2024-6844: Inconsistent CORS Matching Due to Handling of '+' in URL Path in corydolphin/flask-cors
Noroxi assessment
Priority: Monitor (action score 21/100)
- The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
- Probability of exploitation in the next 30 days: 0.31% (FIRST EPSS).
- Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
- According to CISA the attack is automatable: targets can be found by mass scanning.
- Fixed version: python-flask-cors (Debian:11) 3.0.9-2+deb11u1; python-flask-cors (Debian:12) 3.0.10-2+deb12u1; python-flask-cors (Debian:13) 6.0.0-1.
Low priority for now. Upgrade to python-flask-cors (Debian:11) 3.0.9-2+deb11u1; python-flask-cors (Debian:12) 3.0.10-2+deb12u1; python-flask-cors (Debian:13) 6.0.0-1 or later.
Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it
Primary sources: NVD · CVE.org · FIRST EPSS
A vulnerability in corydolphin/flask-cors version 4.0.1 allows for inconsistent CORS matching due to the handling of the '+' character in URL paths. The request.path is passed through the unquote_plus function, which converts the '+' character to a space ' '. This behavior leads to incorrect path normalization, causing potential mismatches in CORS configuration. As a result, endpoints may not be matched correctly to their CORS settings, leading to unexpected CORS policy application. This can cause unauthorized cross-origin access or block valid requests, creating security vulnerabilities and usability issues.
- Published
- Mar 20, 2025
- Updated
- Jun 17, 2026
- EPSS
- 0.3% · 23th percentile
- CWE
- CWE-346
Report tools
Action score
21
Monitor
Low priority for now.
- CVSS
- 21 / 40 · 5.3 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.3%
CISA SSVC decision
- Exploitation
- proof of concept
- Automatable
- yes
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- —
- CNA · @huntr_ai
- 5.3
- NVD has not scored this yet; the score shown is the CNA’s.
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Get told when this record changes
- Not in KEV: no record of exploitation in the wild
- No public exploit code on record
- A fix has been released
If any of these changes, we'll tell you in the daily email digest.
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Noroxi analysis
What does it mean in your environment?
The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.
We use this product, ask for helpAffected systems
Is your version affected?
Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.
| Vendor | Product | CPE |
|---|---|---|
| flask-cors project | flask-cors | cpe:2.3:a:flask-cors_project:flask-cors |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- flask-cors project flask-cors4.0.1
Versions reported by the vendor
Affected version ranges reported by the assigning authority (@huntr_ai). Independent of NVD's CPE analysis and usually ahead of it.
corydolphin corydolphin/flask-cors
- unspecified and later · up to and including latestaffected
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:11 | python-flask-cors | before 3.0.9-2+deb11u1 | 3.0.9-2+deb11u1 |
| Debian:12 | python-flask-cors | before 3.0.10-2+deb12u1 | 3.0.10-2+deb12u1 |
| Debian:13 | python-flask-cors | before 6.0.0-1 | 6.0.0-1 |
| openSUSE:Tumbleweed | python-Flask-Cors | before 6.0.2-1.1 | 6.0.2-1.1 |
| PyPI | flask-cors | before 6.0.0 | 6.0.0 |
Same product
flask-cors project: all recordsOther highest-scoring records for the same primary product.
- CVE-2020-25032An issue was discovered in Flask-CORS (aka CORS Middleware for Flask) before 3.0.9.31Monitor
- CVE-2024-6866Case-Insensitive Path Matching in corydolphin/flask-cors30Monitor
- CVE-2024-6839Improper Regex Path Matching in corydolphin/flask-cors21Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| debian:python-flask-cors | 3.0.10-2+deb12u1 · Debian:12 | Package registry (OSV) |
| opensuse:python-Flask-Cors | 6.0.2-1.1 · openSUSE:Tumbleweed | Package registry (OSV) |
| PyPI:flask-cors | 6.0.0 | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- low · data can be read
- Integrity
- none
- Availability
- none
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- Low
- Integrity impact
- None
- Availability impact
- None
Weakness class (CWE)
CWE-346 · Origin Validation ErrorCVSS vector
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
nvd-secondary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
- JSON Hijacking (aka JavaScript Hijacking)CAPEC-111likelihood: High · High
- Cache PoisoningCAPEC-141likelihood: High · High
- DNS Cache PoisoningCAPEC-142likelihood: High · High
- Exploit Script-Based APIsCAPEC-160Medium
- Exploitation of Trusted IdentifiersCAPEC-21likelihood: High · High
- Application API Message Manipulation via Man-in-the-MiddleCAPEC-384Low
- Transaction or Event Tampering via Application API ManipulationCAPEC-385Medium
- Application API Navigation RemappingCAPEC-386Medium
ATT&CK techniques
- Access Token ManipulationT1134
- Access Token Manipulation:Token Impersonation/TheftT1134.001
- Steal Application Access TokenT1528
- Steal Web Session CookieT1539
- Use Alternate Authentication Material:Web Session CookieT1550.004
- Adversary-in-the-Middle: ARP Cache PoisoningT1557.002
- Compromise Infrastructure: DNS ServerT1584.002
Change log
- Fix✗ → ✓
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References
Vendor advisories and official records. Exploit/PoC links are deliberately left out.