Skip to main content

Flask CVE-2026-27641

CRITICAL
Improper Neutralization of Special Elements Used in a Template Engine (CWE-1336)
2026-02-25 security-advisories@github.com GHSA-65mp-fq8v-56jr
Flask RCE Path Traversal Flask Reuploaded
9.8
CVSS 3.1 · GitHub Advisory
Share

Severity by source

GitHub Advisory PRIMARY
9.8 CRITICAL
AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Primary rating from GitHub Advisory · only source for this CVE.

CVSS VectorGitHub Advisory

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

Lifecycle Timeline

4
Analysis Generated
Mar 12, 2026 - 21:55 vuln.today
PoC Detected
Feb 27, 2026 - 18:40 vuln.today
Public exploit code
Patch released
Feb 27, 2026 - 18:40 nvd
Patch available
CVE Published
Feb 25, 2026 - 04:16 nvd
CRITICAL 9.8

Blast Radius

ecosystem impact
† from your stack dependencies † transitive graph · vuln.today resolves 4-path depth
  • 2 pypi packages depend on flask-reuploaded (2 direct, 0 indirect)

Ecosystem-wide dependent count for version 1.5.0.

DescriptionGitHub Advisory

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.

AnalysisAI

Path traversal and extension bypass in Flask-Reuploaded file upload library. Allows uploading files with arbitrary extensions to arbitrary directories. …

Unlock full vulnerability intelligence

  • Risk assessment & exploitation conditions
  • Attack chain visualization
  • Remediation with exact patch versions
  • Threat intelligence from 22 sources
  • Personal watchlist & email alerts
Continue with Google Continue with GitHub

Free forever · No credit card required

Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata

Access
Send crafted file upload request
Exploit
Bypass extension validation via path traversal
Execution
Inject malicious template syntax
Impact
Execute arbitrary code via SSTI
Sign in to reveal

Vulnerability AssessmentAI

Exploitation Flask-Reuploaded versions prior to 1.5.0 with user-controlled `name` parameter passed to file upload functionality. … Additional conditions and limiting factors are described in the full assessment.
Risk Assessment CVSS 9.8. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in.
Exploit Scenario Attacker uploads PHP/Python web shell by bypassing extension validation and path restrictions, achieves RCE on the server.
Remediation Update Flask-Reuploaded. … Detailed patch versions, workarounds, and compensating controls in full report.
Sign in to read full assessment

Recommended ActionAI

Within 24 hours: Identify all systems and applications using Flask-Reuploaded versions up to 1.5.0 and assess exposure; isolate critical affected systems if patching cannot be completed immediately. …

Sign in for detailed remediation steps and compensating controls.

Threat intelligence, references, and detailed analysis are available after sign-in.

Share

CVE-2026-27641 vulnerability details – vuln.today
Back

This site uses cookies essential for authentication and security. No tracking or analytics cookies are used. Privacy Policy