CVE-2026-54567

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Source

https://cve.org/CVERecord?id=CVE-2026-54567

Import Source

https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-54567.json

JSON Data

https://api.osv.dev/v1/vulns/CVE-2026-54567

Aliases

Published

2026-09-14T17:15:49Z

Modified

2026-09-18T03:30:37Z

Severity

7.5 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H CVSS Calculator

Summary

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

Details

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.

Database specific

{
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
        "CWE-178",
        "CWE-434"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/54xxx/CVE-2026-54567.json",
    "unresolved_ranges": [
        {
            "extracted_events": [
                {
                    "fixed": "1.6.0"
                }
            ],
            "source": "AFFECTED_FIELD"
        }
    ]
}

References

Affected packages

Git / github.com/jugmac00/flask-reuploaded

Affected ranges

Type

GIT

Repo

https://github.com/jugmac00/flask-reuploaded

Events

Introduced

Fixed

5ded76092429c6eb8a4af941b14fbde40a38fff4

Database specific

Show details

{
    "source": "REFERENCES"
}

Affected versions

0.*

0.2.0

Database specific

source

"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-54567.json"