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VulnerabilityPublished

CVE-2026-27641: jugmac00 flask-reuploaded · Template Injection

Affects jugmac00 flask-reuploadedSource CVE Database V5

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

Data as of 29 Oct 2026, 19:04 UTC

CVSS 3.1 base score
9.8Critical
How severe the flaw is on the 0–10 CVSS scale.
EPSS
1.3% chance of exploitation in 30 days – higher than 71% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
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. Weaponized: evidence found.

    Public exploit code: GitHub proofs of concept

  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), GitHub proofs of concept, the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.

What to do

Upgrade jugmac00 flask-reuploaded to 1.5.0.

Affected software

ProductAffectedFixed in
jugmac00flask-reuploadedAffected
  • <1.5.0
Fixed in
  • 1.5.0
PyPIflask-reuploadedpkg:pypi/flask-reuploadedOther threatsAffected
  • <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

To mitigate CVE-2026-27641, organizations should immediately upgrade flask-reuploaded to version 1.5.0 or later, where the vulnerability is patched. Until upgrading is possible, do not pass any user-supplied input to the 'name' parameter in file upload functions; instead, use auto-generated filenames to prevent injection of malicious template code or path traversal sequences. Implement strict input validation and sanitization if the 'name' parameter must be used, ensuring it does not contain special characters, directory traversal patterns, or template syntax. Conduct thorough code reviews and security testing focusing on file upload handling and template rendering logic. Employ runtime application self-protection (RASP) or web application firewalls (WAFs) with rules targeting SSTI and path traversal attempts to detect and block exploitation attempts. Monitor application logs for suspicious file upload activities and unexpected template errors. Finally, educate developers about secure file upload practices and the risks of injecting user input into template engines.

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.

References

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