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CVE-2021-44528· NVD / CVE Program· CNA hackerone

A open redirect vulnerability exists in Action Pack >= 6.0.0 that could allow an attacker to craft a "X-Forwarded-Host" headers in combinati

Noroxi assessment

Priority: Monitor (action score 25/100)

  • A ready-made attack module is public (Nuclei); exploiting it takes no special expertise.
  • Public proof-of-concept code exists (Exploit-DB / GitHub); there is no record of exploitation in the wild.
  • Probability of exploitation in the next 30 days: 4.1% (FIRST EPSS); higher than 90.7% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. A user must open a link or visit a page. No special conditions are required; it is repeatable.
  • Fixed version: rails (Debian:11) 2:6.0.3.7+dfsg-2+deb11u1; rails (Debian:12) 2:6.1.4.6+dfsg-1; rubygem-actionpack-6.0 (openSUSE:Tumbleweed) 6.0.4.4-1.1.

Low priority for now. Upgrade to rails (Debian:11) 2:6.0.3.7+dfsg-2+deb11u1; rails (Debian:12) 2:6.1.4.6+dfsg-1; rubygem-actionpack-6.0 (openSUSE:Tumbleweed) 6.0.4.4-1.1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

A open redirect vulnerability exists in Action Pack >= 6.0.0 that could allow an attacker to craft a "X-Forwarded-Host" headers in combination with certain "allowed host" formats can cause the Host Authorization middleware in Action Pack to redirect users to a malicious website.

MediumCVSS 6.1 · v3.1—Proof of concept Fix available
Published
Jan 10, 2022
Updated
Jun 17, 2026
EPSS
4.1% · 90th percentile

Report tools

JSON

Action score

25

Monitor

Low priority for now.

CVSS
24 / 40 · 6.1 / 10
CISA KEV
0 / 30 · Not listed
EPSS
1 / 30 · 4.1%

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • Proof of concept exists, no weaponized module
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

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When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
rubyonrailsrails

Affected versions

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

  • rubyonrails rails6.0.4.2
  • rubyonrails rails6.1.4.2
  • rubyonrails rails7.0.0

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

    • 6.1.4.2, 6.0.4.2, 7.0.0.rc2affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:11railsbefore 2:6.0.3.7+dfsg-2+deb11u12:6.0.3.7+dfsg-2+deb11u1
Debian:12railsbefore 2:6.1.4.6+dfsg-12:6.1.4.6+dfsg-1
openSUSE:Tumbleweedrubygem-actionpack-6.0before 6.0.4.4-1.16.0.4.4-1.1
RubyGemsactionpackfrom 6.0.0 · before 6.0.4.26.0.4.2
RubyGemsactionpackfrom 6.1.0 · before 6.1.4.26.1.4.2

Same product

rubyonrails: all records

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-2021-22942Oct 18, 2021 · A possible open redirect vulnerability in the Host Authorization middleware in Action Pack >= 6.0.0 that could allow attackers to redirect u
    25Monitor
  • ← EarlierCVE-2011-1497Oct 19, 2021 · A cross-site scripting vulnerability flaw was found in the auto_link function in Rails before version 3.0.6.
    24Monitor
  • Later →CVE-2022-23633Feb 11, 2022 · Exposure of sensitive information in Action Pack
    24Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
debian:rails2:6.1.4.6+dfsg-1 · Debian:12Package registry (OSV)
opensuse:rubygem-actionpack-6.06.0.4.4-1.1 · openSUSE:TumbleweedPackage registry (OSV)
RubyGems:actionpack6.0.4.2Package registry (OSV)
RubyGems:actionpack6.1.4.2Package registry (OSV)

Exploit status

Proof of concept available

A public proof of concept or detection signature exists. Exploit knowledge is out there; don't delay patching.

Evidence

  • Nuclei detection template ×1

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
SourceKindDate
Nuclei detection templateNuclei template CVE-2021-44528 —

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

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

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

The product’s vendor appears in a public program. Matched by name; verify the scope text in the program.

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • A user must open a link or visit a page.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
low · data can be read
Integrity
low · data or configuration can be modified
Availability
none

Impact can extend beyond the vulnerable component (scope changes).

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
Required
Scope
Changed
Confidentiality impact
Low
Integrity impact
Low
Availability impact
None

Weakness class (CWE)

CWE-601 · URL Redirection to Untrusted Site ('Open Redirect')

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

nvd-primary

Attack context

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

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (2 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records