CVE-2021-28556 | Magento Commerce DOM-based cross-site scripting (XSS) could lead to arbitrary javascript execution

Magento versions 2.4.2 (and earlier), 2.4.1-p1 (and earlier) and 2.3.6-p1 (and earlier) are affected by a DOM-based Cross-Site Scripting vulnerability on mage-messages cookies. Successful exploitation could lead to arbitrary JavaScript execution by an unauthenticated attacker. User interaction is required for successful exploitation.

Published: 2021-06-28 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-28556 is rated Moderate Risk (46.7/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 1.40%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2021-28556

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 23.86% 1.40% -22.47%
2 2025-11-21 26.04% 23.86% -2.18%
3 2025-11-18 — 26.04% —

Full EPSS history (14 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-28556

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.9 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:H/I:L/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:H)
They need powerful rights—admin, root, or similar—before this pays off.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 1.7 4.7 [email protected]
4.8 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:H)
They need powerful rights—admin, root, or similar—before this pays off.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 1.7 2.7 [email protected]
3.5 2.0 LOW
AV:N/AC:M/Au:S/C:N/I:P/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:S)
A single authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:N)
No availability impact.
 6.8 2.9 [email protected]

Weakness enumeration for CVE-2021-28556

GitHub Security Advisory for CVE-2021-28556

GHSA-39ch-rg26-gmq5 · Severity: medium · Ecosystem: composer — Magento DOM-based Cross-Site Scripting vulnerability on mage-messages cookies

Affected software / configurations for CVE-2021-28556

Vendor Product Version Raw CPE
magento magento < 2.3.7 cpe:2.3:a:magento:magento:*:*:*:*:commerce:*:*:*
magento magento < 2.3.7 cpe:2.3:a:magento:magento:*:*:*:*:open_source:*:*:*
magento magento >= 2.4.0, <= 2.4.2 cpe:2.3:a:magento:magento:*:*:*:*:commerce:*:*:*
magento magento >= 2.4.0, <= 2.4.2 cpe:2.3:a:magento:magento:*:*:*:*:open_source:*:*:*

References for CVE-2021-28556

cvelogic Threat Intelligence