jugmac00 flask-reuploaded up to 1.4.x Name special elements used in a template engine

Summaryinfo

A vulnerability, which was classified as critical, has been found in jugmac00 flask-reuploaded up to 1.4.x. The affected element is an unknown function. The manipulation of the argument Name leads to improper neutralization of special elements used in a template engine. This vulnerability is referenced as CVE-2026-27641. Remote exploitation of the attack is possible. No exploit is available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability was found in jugmac00 flask-reuploaded up to 1.4.x. It has been rated as critical. This issue affects an unknown functionality. The manipulation of the argument name with an unknown input leads to a improper neutralization of special elements used in a template engine vulnerability. Using CWE to declare the problem leads to CWE-1336. The product uses a template engine to insert or process externally-influenced input, but it does not neutralize or incorrectly neutralizes special elements or syntax that can be interpreted as template expressions or other code directives when processed by the engine. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

Flask-Reuploaded provides file uploads for Flask. A critical path traversal and extension bypass vulnerability in versions prior to 1.5.0 allows remote attackers to achieve arbitrary file write and remote code execution through Server-Side Template Injection (SSTI). Flask-Reuploaded has been patched in version 1.5.0. Some workarounds are available. Do not pass user input to the `name` parameter, use auto-generated filenames only, and implement strict input validation if `name` must be used.

The advisory is shared at github.com. The identification of this vulnerability is CVE-2026-27641 since 02/20/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1221 for this issue.

Upgrading to version 1.5.0 eliminates this vulnerability. Applying the patch d64c6b2f71cb73734fc38baa0e3e156926361288 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-8616). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Vendor

• jugmac00

Name

• flask-reuploaded

Version

• 1.0
• 1.1
• 1.2
• 1.3
• 1.4

License

• open-source

Website

• Product: https://github.com/jugmac00/flask-reuploaded/

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Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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