CVE intelligence and bounded remediation

CVE-2021-21288 — CarrierWave is an open-source RubyGem which provides a simple and flexible way to upload files from Ruby applications

Medium CVSS 4.3

CarrierWave is an open-source RubyGem which provides a simple and flexible way to upload files from Ruby applications. In CarrierWave before versions 1.3.2 and 2.1.1 the download feature has an SSRF vulnerability, allowing attacks to provide DNS entries or IP addresses that are intended for internal use and gather information about the Intranet infrastructure of the platform. This is fixed in versions 1.3.2 and 2.1.1.

Severity
Medium
CVSS
4.3 (3.1)
Published
2021-02-08
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-918

Affected products

  • carrierwave_project / carrierwave

Showing 1 representative product identities from 2 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

Matched remediation archetype

Server-side request forgery and unintended proxying

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Inventory server-side URL fetchers, webhooks, importers, previews, redirects, proxies, and protocol handlers reachable from untrusted input.
  • Map egress paths to internal services, metadata endpoints, loopback, private address space, and privileged control planes.
  • Review DNS resolution, redirect, proxy, credential-forwarding, and URL parsing behavior without requesting sensitive targets.

Remediate safely

  • Replace arbitrary destinations with named integrations or a strict allowlist of schemes, hosts, ports, and paths.
  • Resolve and validate every destination and redirect hop, then enforce egress policy independently of application checks.
  • Remove ambient credentials and sensitive headers from fetchers; apply response size, time, and content limits.

Authoritative sources

Complete CVE record and remediation plan

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