CVE-2026-24486

A Path Traversal vulnerability exists when using non-default configuration options UPLOAD_DIR and UPLOAD_KEEP_FILENAME=True. An attacker can write uploaded files to arbitrary locations on the filesystem by crafting a malicious filename.

Details

When UPLOAD_DIR is set and UPLOAD_KEEP_FILENAME is True, the library constructs the file path using os.path.join(file_dir, fname). Due to the behavior of os.path.join(), if the filename begins with a /, all preceding path components are discarded:

os.path.join("/upload/dir", "/etc/malicious") == "/etc/malicious"

This allows an attacker to bypass the intended upload directory and write files to arbitrary paths.

Affected Configuration

Projects are only affected if all of the following are true:

• UPLOAD_DIR is set
• UPLOAD_KEEP_FILENAME is set to True
• The uploaded file exceeds MAX_MEMORY_FILE_SIZE (triggering a flush to disk)

The default configuration is not vulnerable.

Mitigation

Upgrade to version 0.0.22, or avoid using UPLOAD_KEEP_FILENAME=True in project configurations.

Arbitrary file write to attacker-controlled paths on the filesystem.

Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files. Typical impact: unauthorized file read or write outside the intended directory.

CVE-2026-24486 has a CVSS score of 8.6 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.0.22); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is CVE-2026-24486? CVE-2026-24486 is a high-severity path traversal vulnerability in python-multipart (pip), affecting versions < 0.0.22. It is fixed in 0.0.22. Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files.
2. How severe is CVE-2026-24486? CVE-2026-24486 has a CVSS score of 8.6 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of python-multipart are affected by CVE-2026-24486? python-multipart (pip) versions < 0.0.22 is affected.
4. Is there a fix for CVE-2026-24486? Yes. CVE-2026-24486 is fixed in 0.0.22. Upgrade to this version or later.
5. Is CVE-2026-24486 exploitable, and should I be worried? Whether CVE-2026-24486 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-24486 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-24486? Upgrade python-multipart to 0.0.22 or later.