Werkzeug vulnerable to high resource usage when parsing multipart/form-data containing a large part with CR/LF character at the beginning

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

• palletsprojects werkzeugbefore 2.3.8
• palletsprojects werkzeug3.0.0

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

• pallets werkzeug

  • >= 3.0.0, < 3.0.1, >= 2.0.0rc1, < 2.3.8affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

Other highest-scoring records for the same primary product.

• CVE-2019-14322In Pallets Werkzeug before 0.15.5, SharedDataMiddleware mishandles drive names (such as C:) in Windows pathnames.
  47Plan
• CVE-2022-29361Improper parsing of HTTP requests in Pallets Werkzeug v2.1.0 and below allows attackers to perform HTTP Request Smuggling using a crafted HT
  41Plan
• CVE-2024-34069Werkzeug's improper usage of a pathname and improper CSRF protection results in the remote command execution
  31Monitor
• CVE-2019-14806Pallets Werkzeug before 0.15.3, when used with Docker, has insufficient debugger PIN randomness because Docker containers share the same mac
  31Monitor
• CVE-2023-25577Werkzeug may allow high resource usage when parsing multipart form data with many fields
  30Monitor
• CVE-2026-27199Werkzeug safe_join() allows Windows special device names
  25Monitor

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Root cause

Code that parses nested structures sets no depth or size limit. A small input can turn into a disproportionate processing load.

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

1function expand(node) {2  return node.children.map(expand);3}

1const MAX_DEPTH = 32;2function expand(node, depth = 0) {3  if (depth > MAX_DEPTH) throw new Error("too deep");4  return node.children.map((c) => expand(c, depth + 1));5}

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.