CVE-2026-53538
3.7 · LOWOverview
CVE-2026-53538 is a low-severity vulnerability affecting fastapiexpert python-multipart. It was published on June 22, 2026 and has a CVSS 3.1 base score of 3.7 (LOW).
This vulnerability has a CVSS 3.1 base score of 3.7, rated LOW. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
Technical Description
Python-Multipart is a streaming multipart parser for Python. Prior to 0.0.30, QuerystringParser treated ; as a field separator in application/x-www-form-urlencoded bodies, in addition to &. The WHATWG URL standard, modern browsers, and Python's urllib.parse (since the CVE-2021-23336 fix) treat only & as a separator. This creates a parser differential: the same bytes are tokenized into different fields than a WHATWG compliant intermediary would produce, allowing an attacker to smuggle extra form fields past an upstream body inspecting component. This vulnerability is fixed in 0.0.30.
Remediation
Check the references section for vendor advisories and patches from fastapiexpert. Update python-multipart to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| fastapiexpert | python-multipart | >= 0, < 0.0.30 | Affected |
Frequently Asked Questions
What is CVE-2026-53538?
CVE-2026-53538 is a low-severity vulnerability affecting fastapiexpert python-multipart. It was published on June 22, 2026 and has a CVSS 3.1 base score of 3.7 (LOW).
How severe is CVE-2026-53538?
This vulnerability has a CVSS 3.1 base score of 3.7, rated LOW. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
How do I fix or remediate CVE-2026-53538?
Check the references section for vendor advisories and patches from fastapiexpert. Update python-multipart to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2026-53538?
CyberStrike's AI-powered security agents can automatically detect CVE-2026-53538 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
AI agents map your attack surface to find vulnerabilities like this one.
Automated penetration testing that runs continuously, not just quarterly.
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Browser-based exploitation validates findings with real proof-of-concept.
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