What’s Vulnerable › Vulnerabilities

CVE-2026-27641: Flask-Reuploaded vulnerable to Remote Code Execution via Server-Side Template Injection

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.3% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-02-25 · updated 2026-06-17
• Weakness: CWE-1336

Description

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.

Affected products

• jugmac00 flask-reuploaded: before 1.5.0 — fixed in 1.5.0

How to fix

Upgrade to a fixed version: jugmac00 flask-reuploaded 1.5.0. Check the vendor advisory for mitigations.

References

• https://github.com/jugmac00/flask-reuploaded/commit/d64c6b2f71cb73734fc38baa0e3e156926361288
• https://github.com/jugmac00/flask-reuploaded/pull/180
• https://github.com/jugmac00/flask-reuploaded/security/advisories/GHSA-65mp-fq8v-56jr

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