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VulnerabilityPublished Updated

CVE-2026-54567: jugmac00 flask-reuploaded · Improper Handling of Case Sensitivity

Affects jugmac00 flask-reuploadedSource CVE Database V5

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Not known to be exploited · CVSS 7.5 High : upgrade to 1.6.0 soon.

Data as of 30 Oct 2026, 06:59 UTC

CVSS 3.1 base score
7.5High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.6% chance of exploitation in 30 days – higher than 49% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 1.6.0
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 14 Sep 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: 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 29 Oct 2026.

What to do

Upgrade jugmac00 flask-reuploaded to 1.6.0.

Affected software

ProductAffectedFixed in
jugmac00flask-reuploadedAffected
  • <1.6.0
Fixed in
  • 1.6.0
PyPIflask-reuploadedpkg:pypi/flask-reuploadedOther threatsAffected
  • <1.6.0
Fixed in
  • 1.6.0

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

AI-suggested

This vulnerability is fixed in flask-reuploaded version 1.6.0. Users should upgrade to version 1.6.0 or later to remediate the issue. Until upgraded, avoid using denylist configurations for file extensions and prefer allowlist configurations. Also, ensure that the deployment environment treats file extensions case-sensitively if possible. No other immediate actions are indicated by the vendor advisory.

Description

Flask-Reuploaded provides file uploads for Flask. From 1.5.0 until 1.6.0, UploadSet.save(storage, name=...) in src/flask_uploads/flask_uploads.py applies lowercase_ext to the default upload path but uses the case-preserving extension helper for a caller-supplied name before extension_allowed evaluates an AllExcept denylist. An attacker who controls the name override can use a mixed-case dangerous extension to bypass a lowercase denylist and store the file in the served upload directory. Exploitation requires a denylist configuration, a user-influenced name override, and a deployment that resolves or executes extensions case-insensitively; pure allowlists remain protected and path containment is not bypassed. On an execution-capable upload directory, the stored file can execute with the web server's privileges and affect confidentiality, integrity, and availability. This issue is fixed in version 1.6.0.

References

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