A missing input validation in Nextcloud Server before 20.0.2, 19.0.5, 18.0.11 allows users to store unlimited data in workflow rules causing

Affected versions

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

• nextcloud nextcloud serverbefore 18.0.11
• nextcloud nextcloud server19.0.0 and later · before 19.0.5
• nextcloud nextcloud server20.0.0 and later · before 20.0.2

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.

• n/a Nextcloud Server

  • Fixed in 20.0.2, 19.0.5, 18.0.11affected

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-2021-32802Preview generation used third-party library not suited for user-generated content in Nextcloud server
  40Plan
• CVE-2021-32726Webauthn tokens not removed after user has been deleted
  40Plan
• CVE-2021-22915Nextcloud server before 19.0.11, 20.0.10, 21.0.2 is vulnerable to brute force attacks due to lack of inclusion of IPv6 subnets in rate-limit
  40Plan
• CVE-2023-49792Bruteforce protection can be bypassed with misconfigured proxy
  39Monitor
• CVE-2023-48306Nextcloud Server DNS pin middleware can be tricked into DNS rebinding allowing SSRF
  39Monitor
• CVE-2021-32654Attacker can obtain write access to any federated share/public link
  37Monitor

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.