PatchTheCVECVE-2026-53540: Python-Multipart is a streaming multipart parser for Python
CVE-2026-53540 is a low-severity flaw (CVSS 3.7) affecting python-multipart. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
Python-Multipart is a streaming multipart parser for Python. Prior to 0.0.31, parse_form() did not validate the Content-Length header before using it to bound its chunked read of the request body. A negative Content-Length turned the bounded read into a read-until-EOF, so the entire body was loaded into memory in a single read instead of in fixed-size chunks. This vulnerability is fixed in 0.0.31.
Why this priority
- Remotely exploitable, no login, no user action
A fixed release or distro patch exists.
Risk facts
| CVSS score | 3.7 (Low) |
| Attack vector | Network (remote) |
| Attack complexity | High |
| Privileges needed | None |
| User interaction | None |
| EPSS exploit chance | 0.3% (top 73%) |
| CISA exploited list | No |
| Weakness | CWE-1284 |
| Published | 2026-06-22 |
| Last modified | 2026-10-25 |
Last updated 2026-10-25 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2026-53540?
python-multipart: upgrade to 0.0.31. Exact commands for each OS are on this page.
Is CVE-2026-53540 being exploited?
CVE-2026-53540 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2026-53540 affect?
CVE-2026-53540 affects python-multipart. Severity is low (CVSS 3.7). Python-Multipart is a streaming multipart parser for Python. Prior to 0.0.31, parse_form() did not validate the Content-Length header before using it to bound its chunked read of the request body. A negative Content-Length turned the bounde
How urgent is CVE-2026-53540?
Priority 25/100. Remotely exploitable, no login, no user action
Software pages
Related CVEs
- CVE-2026-53539 HIGH 7.5 UPGRADE Python-Multipart is a streaming multipart parser for Python
- CVE-2026-53537 LOW 3.7 UPGRADE Python-Multipart is a streaming multipart parser for Python
- CVE-2026-53538 LOW 3.7 UPGRADE Python-Multipart is a streaming multipart parser for Python