Unauthenticated code execution via unchecked upload name
Published Feb 25, 2026 · Updated Feb 25, 2026
Path traversal in jugmac00 Flask-Reuploaded before 1.5.0 allows remote attackers to write arbitrary files through crafted upload names. UploadSet.save() replaces the validated storage filename with a caller-supplied name, then builds the destination without sanitizing it, revalidating its extension, or checking path containment. Exploitation requires a Flask application to pass attacker-controlled input as name; a written template or executable file enables server-side code execution.
Summary
What happened
Path traversal in jugmac00 Flask-Reuploaded before 1.5.0 allows remote attackers to write arbitrary files through crafted upload names. UploadSet.save() replaces the validated storage filename with a caller-supplied name, then builds the destination without sanitizing it, revalidating its extension, or checking path containment. Exploitation requires a Flask application to pass attacker-controlled input as name; a written template or executable file enables server-side code execution.
The record
- CVE
- CVE-2026-27641
- Published
- Feb 25, 2026
- Updated
- Feb 25, 2026
- Vendor
- jugmac00
- Product
- Flask-Reuploaded
- Classifications
- CWE-1336, CWE-22, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Feb 25, 2026CVE publishedPublication date reported by the CVE source.
- Feb 25, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 1.5.0
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo