CVE-2026-53540 — Python-Multipart: Negative Content-Length in parse_form buffers the entire body in memory
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 o…
Published: 2026-06-22 · CVSS: 3.7 · CVSS 3.1
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.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7