Skip to content
Patch Next
Sign inAdd to your agent

← Actionable
High, CVSS 7.5amended

Flask-Reuploaded: Extension-denylist bypass via case-folding asymmetry in name-override path (incomplete-fix variant of CVE-2026-27641)

CVE-2026-54567GHSA-937x-gpqr-72gg

What to do

Vendor fix available. Upgrade each affected package to the fixed version on its release line (flask-reuploaded 1.6.0), redeploy, then verify what is actually installed.

This page has no inventory attached, so it cannot say whether you are affected. A vendor fix is not proof that your deployment is fixed.

Add to your agent

Affected packages

Sources

Severity and exploitation
Exploitation
No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.
CVSS
7.5 · CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS
  • CVE-2026-54567: 0.63% estimated exploitation activity in the next 30 days; percentile 50.06 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.
Source description

As published by the source; long descriptions are shortened.

1. Header | Field | Value | |---|---| | Title | Extension-denylist bypass via case-folding asymmetry in name-override path (incomplete-fix variant of CVE-2026-27641) | | Project | Flask-Reuploaded (flaskuploads) | | Affected | <= 1.5.0 (latest release; commit ae31c3f91da40b465ca5e8f57d93f063b4553e23) | | Relationship | Incomplete-fix variant of CVE-2026-27641 (fixed in v1.5.0; this variant survives that fix) | | CWE | CWE-434 (Unrestricted Upload of File with Dangerous Type) + CWE-178 (Improper Handling of Case Sensitivity) | | CVSS v3.1 (proposed) | ~7.0–7.3 (High, conditional) — CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H. Final score deferred to maintainer. | | Verified against | pip install Flask-Reuploaded==1.5.0, Python 3.11 | --- 2. Decisive evidence — the asymmetry The v1.5.0 fix for CVE-2026-27641 added an extension re-validation that runs when a caller supplies a name override to UploadSet.save(). It is routed through the case-preserving extension() helper, whereas the…

Dates and revisions
Published by the source
Last modified by the source
Source last checked
  1. Revision 2 · amended ·

    Amended from ghsa record GHSA-937x-gpqr-72gg

  2. Revision 1 · created ·

    Published from osv record GHSA-937x-gpqr-72gg

Agent brief

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: CVE-2026-54567

Advisory: Flask-Reuploaded: Extension-denylist bypass via case-folding asymmetry in name-override path (incomplete-fix variant of CVE-2026-27641)
IDs: CVE-2026-54567, GHSA-937x-gpqr-72gg
Record: https://patchnext.com/advisories/cve-2026-54567 (revision 2, source checked 26 Oct 2026, 13:49 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: flask-reuploaded 1.6.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI flask-reuploaded: affected <= 1.5.0; fixed in 1.6.0

## Suggested inspection (read-only)
- `python -m pip show flask-reuploaded`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on flask-reuploaded.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-937x-gpqr-72gg (OSV record GHSA-937x-gpqr-72gg lists affected ranges: PyPI flask-reuploaded >=0 <1.6.0 (fixed))
- Verified: https://github.com/advisories/GHSA-937x-gpqr-72gg (GitHub-reviewed advisory GHSA-937x-gpqr-72gg lists affected ranges: PyPI flask-reuploaded >=0 <=1.5.0)

Commands are suggestions: review each one before running it.

Loading voting…