There is a possible DoS vulnerability in the multipart parser in Rack before 2.0.6.

Affected versions

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

• rack project rack2.0.4
• rack project rack2.0.5

Versions reported by the vendor

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

• Rack Rack

  • 2.0.6affected

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-2022-30123A sequence injection vulnerability exists in Rack <2.0.9.1, <2.1.4.1 and <2.2.3.1 which could allow is a possible shell escape in the Lint a
  41Plan
• CVE-2020-8161A directory traversal vulnerability exists in rack < 2.2.0 that allows an attacker perform directory traversal vulnerability in the Rack::Di
  35Monitor
• CVE-2022-30122A possible denial of service vulnerability exists in Rack <2.0.9.1, <2.1.4.1 and <2.2.3.1 in the multipart parsing component of Rack.
  31Monitor
• CVE-2020-8184A reliance on cookies without validation/integrity check security vulnerability exists in rack < 2.2.3, rack < 2.1.4 that makes it is possib
  31Monitor
• CVE-2018-16471There is a possible XSS vulnerability in Rack before 2.0.6 and 1.6.11.
  25Monitor
• CVE-2015-3225lib/rack/utils.rb in Rack before 1.5.4 and 1.6.x before 1.6.2, as used with Ruby on Rails 3.x and 4.x and other products, allows remote atta
  22Monitor

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.