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VulnerabilityPublished Updated

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

Affects flask-reuploadedSource GCVE Database

0
Authoritative record:CVE-2026-27641· Critical 9.8

Not known to be exploited · CVSS 9.8 Critical : upgrade to 1.5.0 as a priority.

Data as of 27 Oct 2026, 17:29 UTC

CVSS 3.1 base score
9.8Critical
How severe the flaw is on the 0–10 CVSS scale.
Patch
Available – fixed in 1.5.0
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 25 Feb 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade flask-reuploaded to 1.5.0.

Affected software

ProductAffectedFixed in
PyPIflask-reuploadedAffected
  • <1.5.0
Fixed in
  • 1.5.0

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A patch is available and included in Flask-Reuploaded version 1.5.0; upgrading to this version fully mitigates the vulnerability. Until upgrading, do not pass user input directly to the 'name' parameter when saving files. Use auto-generated filenames or sanitize and validate any user-supplied filenames using secure_filename and strict extension checks as demonstrated in the vendor's recommended workaround.

Description

Flask-Reuploaded versions prior to 1.5.0 contain a critical vulnerability allowing remote code execution via Server-Side Template Injection (SSTI). This flaw involves path traversal and extension bypass, enabling attackers to write arbitrary files. The issue is fixed in version 1.5.0. Mitigations include avoiding user input in the 'name' parameter, using auto-generated filenames, or applying strict input validation and sanitization.

References

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