In actionpack gem >= 6.0.0, a possible XSS vulnerability exists when an application is running in development mode allowing an attacker to s

Affected versions

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

• rubyonrails rails6.0.0 and later · before 6.0.3.4

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 https://github.com/rails/rails

  • 6.0.3.4affected

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-2019-5418There is a File Content Disclosure vulnerability in Action View <5.2.2.1, <5.1.6.2, <5.0.7.2, <4.2.11.1 and v3 where specially crafted accepKEV
  90Now
• CVE-2016-0752Directory traversal vulnerability in Action View in Ruby on Rails before 3.2.22.1, 4.0.x and 4.1.x before 4.1.14.1, 4.2.x before 4.2.5.1, anKEV
  89Now
• CVE-2019-5420A remote code execution vulnerability in development mode Rails <5.2.2.1, <6.0.0.beta3 can allow an attacker to guess the automatically gene
  66This week

Published before and after this one in the same product

• ← EarlierCVE-2020-8166Jul 2, 2020 · A CSRF forgery vulnerability exists in rails < 5.2.5, rails < 6.0.4 that makes it possible for an attacker to, given a global CSRF token suc
  18Monitor
• ← EarlierCVE-2020-8185Jul 2, 2020 · A denial of service vulnerability exists in Rails <6.0.3.2 that allowed an untrusted user to run any pending migrations on a Rails app runni
  27Monitor
• Later →CVE-2021-22880Feb 11, 2021 · The PostgreSQL adapter in Active Record before 6.1.2.1, 6.0.3.5, 5.2.4.5 suffers from a regular expression denial of service (REDoS) vulnera
  31Monitor

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

Root cause

User content is inserted into the page as HTML. The browser interprets the content as code rather than data.

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

1commentEl.innerHTML = comment.body;

1commentEl.textContent = comment.body;

Attack context

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