CVE-2021-21288Network attack vector

Intranet probing via unrestricted remote downloads

Published Feb 8, 2021 · Updated Aug 3, 2024

SSRF in CarrierWave's remote-download feature before 1.3.2 and 2.0.0 through 2.1.0 allows remote authenticated users to probe intranet services. CarrierWave::Downloader::Base#download passes the supplied URL to OpenURI.open_uri without blocking loopback, link-local, or private destinations. Exposure requires a host application to accept a user-controlled remote upload URL, and successful requests disclose reachable internal resources through downloaded response content.

CVSS severity4.3
Medium
EPSS probability1.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

SSRF in CarrierWave's remote-download feature before 1.3.2 and 2.0.0 through 2.1.0 allows remote authenticated users to probe intranet services. CarrierWave::Downloader::Base#download passes the supplied URL to OpenURI.open_uri without blocking loopback, link-local, or private destinations. Exposure requires a host application to accept a user-controlled remote upload URL, and successful requests disclose reachable internal resources through downloaded response content.

The record

CVE
CVE-2021-21288
Published
Feb 8, 2021
Updated
Aug 3, 2024
Vendor
CarrierWave
Product
CarrierWave
Classifications
CWE-918, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 8, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 1.3.2
  2. Affected versionversion=>= 2.0.0, < 2.1.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

CarrierWave · CarrierWaveversion=< 1.3.2; version=>= 2.0.0, < 2.1.1

Published CVSS scores

4.3GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
4.0NIST NVDAV:N/AC:L/Au:S/C:P/I:N/A:N
4.3NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-918Server-Side Request Forgery (SSRF)
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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