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Response snapshot Oct 27, 2026, 17:26 UTC

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VulnerabilityCVE-2026-27641

Flask-Reuploaded vulnerable to Remote Code Execution via Server-Side Template Injection

1. **Do not pass user input to the `name` parameter** 2. Use auto-generated filenames only 3. Implement strict input validation if `name` must be used ```python from werkzeug.utils import secure_filename import os

Published Updated

At a glance

Exploited
Not known
Severity
9.8 Critical (CVSS 3.1)
Chance of exploitation
Not estimated
Sources
1 source

What to do

GitHub lists first patched versions: flask-reuploaded: 1.5.0. Confirm the affected range and upgrade guidance in the exact advisory.

Read GitHub-reviewed advisory GHSA-65mp-fq8v-56jr (opens a new tab)

What happened

### Impact A critical path traversal and extension bypass vulnerability in Flask-Reuploaded allows remote attackers to achieve arbitrary file write and remote code execution through Server-Side Template Injection (SSTI).

### Patches Flask-Reuploaded has been patched in version 1.5.0

### Workarounds

1. **Do not pass user input to the `name` parameter** 2. Use auto-generated filenames only 3. Implement strict input validation if `name` must be used

Continue reading

```python from werkzeug.utils import secure_filename import os

# Sanitize user input before passing to save() safe_name = secure_filename(request.form.get('custom_name')) # Remove path separators safe_name = os.path.basename(safe_name) # Validate extension matches policy if not photos.extension_allowed(photos.get_extension(safe_name)): abort(400)

filename = photos.save(file, name=safe_name) ```

### Resources The fix is documented in the pull request, see https://github.com/jugmac00/flask-reuploaded/pull/180.

A proper write-up was created by the reporter of the vulnerability, Jaron Cabral (https://www.linkedin.com/in/jaron-cabral-751994357/), but is not yet available as of time of this publication.

Affected package ranges reported by GitHub: flask-reuploaded: < 1.5.0

Scores and how they were measured

CVSS base severity

9.8

Version 3.1As of

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Measurement source (opens a new tab)

How bad it is if exploited. Not a prediction of exploitation or proof you are exposed.

EPSS probability

Not available

A model's estimate of exploitation in the next 30 days, not certainty or your own risk.

Related technology

Sources

  1. Primary source

    GitHub-reviewed advisory GHSA-65mp-fq8v-56jr (opens a new tab)

    The public advisory supplies the description, affected package/version ranges, and any listed CVSS metric. GitHub review is not local review.

    Published Checked

  2. Primary source

    GitHub public advisory API page (opens a new tab)

    The API page supplied GHSA-65mp-fq8v-56jr, its actual identifiers, source dates, and structured metrics.

    Published Date not suppliedChecked

Cite this record

For factual claims, cite the primary sources above; cite KEVWire for its compilation, dates, and classifications.

APA

KEVWire. (2026, October 27). Flask-Reuploaded vulnerable to Remote Code Execution via Server-Side Template Injection (CVE-2026-27641). https://kevwire.com/record/CVE-2026-27641

MLA

"Flask-Reuploaded vulnerable to Remote Code Execution via Server-Side Template Injection (CVE-2026-27641)." KEVWire, 27 Oct. 2026, kevwire.com/record/CVE-2026-27641.

Chicago

KEVWire. "Flask-Reuploaded vulnerable to Remote Code Execution via Server-Side Template Injection (CVE-2026-27641)." Last modified October 27, 2026. https://kevwire.com/record/CVE-2026-27641.

Evidence summary (plain text)

Flask-Reuploaded vulnerable to Remote Code Execution via Server-Side Template Injection (Feb 25, 2026).
1. **Do not pass user input to the `name` parameter**
2. Use auto-generated filenames only
3. Implement strict input validation if `name` must be used

```python
from werkzeug.utils import secure_filename
import os
CVSS 9.8 (version 3.1; evidence as of Oct 27, 2026; https://github.com/advisories/GHSA-65mp-fq8v-56jr).
Sources:
GitHub-reviewed advisory GHSA-65mp-fq8v-56jr: https://github.com/advisories/GHSA-65mp-fq8v-56jr
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc
Record ID: CVE-2026-27641.
Record origin: Ingested record.
AI evidence: Not assessed.
Known exploitation: Not assessed.
Zero-day status: Not assessed. KEV membership alone does not establish zero-day status.
About this data

This record was ingested from a data source. Retrieved: Oct 27, 2026, 17:25 UTC. Ingestion is not an independent editorial investigation.

A CISA KEV listing documents known exploitation, not necessarily a zero-day; absence from the catalog does not prove a vulnerability has never been exploited.

Technology tags indicate possible relevance, not verified exposure. Confirm the affected product, version, and configuration against your own inventory; KEVWire does not scan your systems.

A personal reading checklist on this device, not verified remediation.

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