Vulnerability · Published Feb 25, 2026 · Assigned by GitHub_M
CVE-2026-27641Flask-Reuploaded vulnerable to Remote Code Execution via Server-Side Template Injection
Critical 9.8
In plain English
A critical-severity security flaw in flask-reuploaded from jugmac00. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.3% (higher than 71% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code. Fixed versions are available - upgrade the affected package.
Official 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 packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| PyPI | flask-reuploaded | 1.5.0 | GHSA-65mp-fq8v-56jr |
| PyPI | flask-reuploaded | 1.5.0 | PYSEC-2026-341 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| jugmac00 | flask-reuploaded | < 1.5.0 |
Weakness: CWE-1336 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H