---
id: "CVE-2026-116133"
kind: "vulnerability"
aliases: ["CVE-2026-116133"]
title: "Perl HTTP::Body: malformed multipart upload burns CPU via quadratic rescanning"
severity: "medium"
cvss: null
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["catalyst", "package", "perl", "psgi", "self-hosted", "web-apps"]
not_affected_if: ["body-size-capped-at-proxy", "no-multipart-uploads"]
published_at: "2026-10-28T18:17:12+00:00"
first_seen_at: "2026-10-28T18:34:33+00:00"
updated_at: "2026-10-28T18:35:36+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-116133", "first_seen_at": "2026-10-28T18:34:33+00:00"}]
---

# Perl HTTP::Body: malformed multipart upload burns CPU via quadratic rescanning

HTTP::Body, a Perl module that parses form and multipart request bodies, rescans its whole buffer for each new chunk when a multipart body has a missing or malformed boundary. A remote attacker can send a few such requests to exhaust worker CPU and slow or stall the service.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Run `perl -MHTTP::Body -e 'print $HTTP::Body::VERSION'` or `cpanm --info HTTP::Body` to read the installed version
- Check the lockfile or `cpanfile.snapshot` for the HTTP::Body version in use

## Fix

- Upgrade HTTP::Body to `1.23_01` or later
- Until upgraded, cap the request body size at the web server or proxy so oversized multipart uploads are rejected early

## Timeline

- 2026-10-28T18:34:33+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-116133

## From the sources

HTTP::Body versions before 1.23_01 for Perl allow CPU exhaustion via quadratic rescanning of a multipart body with a missing or malformed boundary.

Before the first part, and between parts, the multipart parser searches the whole buffered body for the next boundary. On a miss it keeps everything and searches again from the start when the next chunk arrives. A body with no boundary, or with a delimiter followed by neither CRLF nor "--", is therefore rescanned on every chunk, taking time quadratic in its size.

A remote attacker can exhaust worker CPU with a few such requests.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_