No exploitation reportedFix available

CVE-2021-44528

Q: Is CVE-2021-44528 actively exploited?

Active exploitation of CVE-2021-44528 has not been confirmed. Its EPSS score was 4.2% on 2026-10-23, the estimated probability of exploitation in the next 30 days.

Q: What is the CVSS score for CVE-2021-44528?

CVE-2021-44528 has a CVSS v3 base score of 6.1 (MEDIUM severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

No exploitation reported by the sources we read.

Published2022-01-10
WeaknessCWE-601

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

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.

Timeline

dates in UTC

2022-01-1014:10CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-44528?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-44528?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD · OSV

Ruby on Rails

Branch	Affected	Fixed in	Source
6.0	= 6.0.4.2	no fix published	NVD
6.1	= 6.1.4.2	no fix published	NVD
7.0	= 7.0.0	no fix published	NVD

actionpack

Branch	Affected	Fixed in	Source
6.1	≥ 6.1.0, < 6.1.4.2	6.1.4.2	OSV
6.0	≥ 6.0.0, < 6.0.4.2	6.0.4.2	OSV

rails

Branch	Affected	Fixed in	Source
7.0	≥ 7.0.0-rc2, ≤ 7.0.0-rc2	no fix published	OSV

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

Advisories and patches

github.comPatch

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

NVDCVSS 3.16.1read 2026-10-23
NVDCVSS 2.05.8read 2026-10-23
CNAweakness (CWE)CWE-601read 2026-10-23
NVDweakness (CWE)CWE-601read 2026-10-23
FIRST EPSSEPSS score4.2 %2026-10-23
OSVaffected packages—

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Published: 2022-01-10
Last Modified: 2026-06-17
NVD status: Modified

Frequently asked questions

What is CVE-2021-44528?

Is CVE-2021-44528 actively exploited?

Active exploitation of CVE-2021-44528 has not been confirmed. Its EPSS score was 4.2% on 2026-10-23, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-44528?

CVE-2021-44528 has a CVSS v3 base score of 6.1 (MEDIUM severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

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