Affected: defnull multipart, Red Hat AI Inference Server 3.2, Red Hat OpenShift AI 2.25, Red Hat OpenShift AI 3.3, Red Hat Lightspeed Core, Red Hat OpenShift Lightspeed, Red Hat AI Inference Server, Red Hat Ansible Automation Platform 2, Red Hat Enterprise Linux AI (RHEL AI) 3, Red Hat OpenShift AI (RHOAI) and 1 more

multipart is a fast multipart/form-data parser for python. Prior to 1.2.2, 1.3.1 and 1.4.0-dev, the parse_options_header() function in multipart.py uses a regular expression with an ambiguous alternation, which can cause exponential backtracking (ReDoS) when parsing maliciously crafted HTTP or multipart segment headers. This can be abused for denial of service (DoS) attacks against web applications using this library to parse request headers or multipart/form-data streams. The issue is fixed in 1.2.2, 1.3.1 and 1.4.0-dev.

Affected: Ubuntu:25.10: multipart, Ubuntu:26.04:LTS: multipart

It was discovered that multipart had an ambiguous regular expression alternation when handling certain HTTP header values. A remote attacker could possibly use this issue to cause multipart to use excessive resources, leading to a denial of service.