VulnerabilityPublished 20 Mar 2025Updated 3 Nov 2025

CVE-2024-6866: Flask-CORS vulnerable to Improper Handling of Case Sensitivity

Affects flask-corsSource GCVE Database

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Authoritative record:CVE-2024-6866· Medium 5.3

Not known to be exploited · CVSS 5.3 Medium : upgrade to 6.0.0 when convenient.

Data as of 30 Oct 2026, 01:19 UTC

CVSS 3.0 base score

5.3Medium

How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none

CVSS scores by source
CNA (@huntr_ai)	CVSS 3.0	5.3

Patch: Available – fixed in 6.0.0

CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N

Attack Vector: Network
Attack Complexity: High
Privileges Required: None
User Interaction: Required
Scope: Unchanged
Confidentiality: High
Integrity: None
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: High: A successful attack depends on conditions beyond the attacker's control. That is, a successful attack cannot be accomplished at will, but requires the attacker to invest in some measurable amount of effort in preparation or execution against the vulnerable component before a successful attack can be expected. For example, a successful attack may require an attacker to: gather knowledge about the environment in which the vulnerable target/component exists; prepare the target environment to improve exploit reliability; or inject themselves into the logical network path between the target and the resource requested by the victim in order to read and/or modify network communications (e.g., a man in the middle attack).
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 3 Nov 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade flask-cors to 6.0.0.

Affected software

Product	Affected	Fixed in
PyPIflask-cors	Affected <6.0.0	Fixed in 6.0.0

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Upgrade flask-cors to version 6.0.0 or later, where the issue with case-insensitive path matching is fixed. Since a patch is available and the vulnerability is addressed in the fixed version, applying this official fix is the recommended remediation.

Description

Flask-CORS versions prior to 6.0.0 have a vulnerability where request path matching is incorrectly handled in a case-insensitive manner. This occurs because the `try_match` function, designed for host matching, is used for path matching, which should be case-sensitive. This flaw can allow unauthorized origins to access restricted paths, potentially exposing sensitive data. The issue is fixed in version 6.0.0.

Impact

This vulnerability can lead to unauthorized access to paths that are intended to be restricted by origin policies, resulting in potential data exposure and leaks. The CVSS score of 5.3 (medium severity) reflects the network attack vector with high impact on confidentiality but no impact on integrity or availability. Exploitation requires user interaction and has a high attack complexity.

Summary

The flask-cors library version 5.0.1 and earlier improperly handles case sensitivity in request path matching due to the use of the `try_match` function originally intended for host matching. Paths in URLs are case-sensitive, but the regex matching applied is case-insensitive, causing a mismatch that can lead to unauthorized origins accessing restricted paths. This vulnerability is tracked as CVE-2024-6866 and is fixed in flask-cors version 6.0.0.

CWE-178Improper Handling of Case Sensitivity (opens in a new tab)
Base weakness
The product does not properly account for differences in case sensitivity when accessing or determining the properties of a resource, leading to inconsistent results.
Architecture and Design · Input Validation
Avoid making decisions based on names of resources (e.g. files) if those resources can have alternate names.
Implementation · Input Validation
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
Implementation · Input Validation
Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174).
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 30 Oct 2026, 01:19 UTC

WeaknessesCWE-178

Technical details

References

Community reviews

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