How severe is CVE-2021-42237?

CVE-2021-42237 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-42237 being actively exploited?

Yes. CVE-2021-42237 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2022-03-25, which means active exploitation has been confirmed. It should be prioritised for remediation.

What products are affected by CVE-2021-42237?

CVE-2021-42237 primarily affects Sitecore Experience Platform. In total, 24 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-42237?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.

Does CVE-2021-42237 have an EU (EUVD) identifier?

Yes. CVE-2021-42237 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2021-29215. It is also flagged as exploited in the EUVD (since 2022-03-25).

When was CVE-2021-42237 published?

CVE-2021-42237 was published on 2021-11-05 and last updated on 2026-07-09.

CVE-2021-42237

CVE-2021-42237 is a critical-severity vulnerability in Sitecore Experience Platform with a CVSS 3.x base score of 9.8. It is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog, confirming it has been exploited in the wild (added 2022-03-25). The underlying weakness is classified as CWE-502.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 10.0
EPSS exploit prediction: 98% (100th percentile)
Actively exploited: Yes — listed in CISA KEV (added 2022-03-25)
EU (EUVD) id: EUVD-2021-29215
EU exploitation: Flagged exploited in the ENISA EU Vulnerability Database (since 2022-03-25)
Weakness: CWE-502
Affected product: Sitecore Experience Platform
Published: 2021-11-05
Last modified: 2026-07-09

Description

Sitecore XP 7.5 Initial Release to Sitecore XP 8.2 Update-7 is vulnerable to an insecure deserialization attack where it is possible to achieve remote command execution on the machine. No authentication or special configuration is required to exploit this vulnerability.

Frequently asked questions

What is CVE-2021-42237?: Sitecore XP 7.5 Initial Release to Sitecore XP 8.2 Update-7 is vulnerable to an insecure deserialization attack where it is possible to achieve remote command execution on the machine. No authentication or special configuration is required to exploit this vulnerability.
How severe is CVE-2021-42237?: CVE-2021-42237 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-42237 being actively exploited?: Yes. CVE-2021-42237 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2022-03-25, which means active exploitation has been confirmed. It should be prioritised for remediation.
What products are affected by CVE-2021-42237?: CVE-2021-42237 primarily affects Sitecore Experience Platform. In total, 24 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-42237?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.
Does CVE-2021-42237 have an EU (EUVD) identifier?: Yes. CVE-2021-42237 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2021-29215. It is also flagged as exploited in the EUVD (since 2022-03-25).
When was CVE-2021-42237 published?: CVE-2021-42237 was published on 2021-11-05 and last updated on 2026-07-09.

References

EU advisories (EUVD)

http://sitecore.com

Affected products (24)

cpe:2.3:a:sitecore:experience_platform:7.5:-:*:*:*:*:*:*
cpe:2.3:a:sitecore:experience_platform:7.5:update1:*:*:*:*:*:*
cpe:2.3:a:sitecore:experience_platform:7.5:update2:*:*:*:*:*:*
cpe:2.3:a:sitecore:experience_platform:8.0:-:*:*:*:*:*:*
cpe:2.3:a:sitecore:experience_platform:8.0:sp1:*:*:*:*:*:*
cpe:2.3:a:sitecore:experience_platform:8.0:update1:*:*:*:*:*:*
cpe:2.3:a:sitecore:experience_platform:8.0:update2:*:*:*:*:*:*
cpe:2.3:a:sitecore:experience_platform:8.0:update3:*:*:*:*:*:*
cpe:2.3:a:sitecore:experience_platform:8.0:update4:*:*:*:*:*:*
cpe:2.3:a:sitecore:experience_platform:8.0:update5:*:*:*:*:*:*
cpe:2.3:a:sitecore:experience_platform:8.0:update6:*:*:*:*:*:*
cpe:2.3:a:sitecore:experience_platform:8.0:update7:*:*:*:*:*:*
cpe:2.3:a:sitecore:experience_platform:8.1:-:*:*:*:*:*:*
cpe:2.3:a:sitecore:experience_platform:8.1:update1:*:*:*:*:*:*
cpe:2.3:a:sitecore:experience_platform:8.1:update2:*:*:*:*:*:*
cpe:2.3:a:sitecore:experience_platform:8.1:update3:*:*:*:*:*:*
cpe:2.3:a:sitecore:experience_platform:8.2:-:*:*:*:*:*:*
cpe:2.3:a:sitecore:experience_platform:8.2:update1:*:*:*:*:*:*
cpe:2.3:a:sitecore:experience_platform:8.2:update2:*:*:*:*:*:*
cpe:2.3:a:sitecore:experience_platform:8.2:update3:*:*:*:*:*:*
cpe:2.3:a:sitecore:experience_platform:8.2:update4:*:*:*:*:*:*
cpe:2.3:a:sitecore:experience_platform:8.2:update5:*:*:*:*:*:*
cpe:2.3:a:sitecore:experience_platform:8.2:update6:*:*:*:*:*:*
cpe:2.3:a:sitecore:experience_platform:8.2:update7:*:*:*:*:*:*

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