CVE-2025-53690: Sitecore Multiple Products Deserialization of Untrusted Data Vulnerability

Is it exploited?

Yes. CISA added it to the Known Exploited Vulnerabilities catalog on 4 Sep 2025, 1 day after the CVE record was published.

How likely is exploitation in the next 30 days?

60.6%

EPSS score, percentile 99.1 of all scored records

How severe?

9.0 Critical

CVSS v3.1 base score, given by the CNA

What should I do?

CISA deadline 25 Sep 2025. Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

The CVE record links no vendor advisory, patch or mitigation.

Which versions are affected?

Affected

• 9.0 and earlier
• 9.0 and earlier

Versions by product

Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.

What to do

CISA due date for this action: 25 September 2025.

Advisories and patches

The CVE record links no vendor advisory, patch or mitigation.

Linked from CISA's catalog entry

• https://support.sitecore.com/kb?id=kb_article_view&sysparm_article=KB1003865
• https://nvd.nist.gov/vuln/detail/CVE-2025-53690

Affected products and versions

As listed in the CVE record.

Versions not listed are: unaffected.

Versions not listed are: unaffected.

Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.

About this vulnerability

Sitecore Experience Manager (XM), Experience Platform (XP), Experience Commerce (XC), and Managed Cloud contain a deserialization of untrusted data vulnerability involving the use of default machine keys. This flaw allows attackers to exploit exposed ASP.NET machine keys to achieve remote code execution.

Summary: CISA's KEV catalog, as of 28 Oct 2026.

• CISA added CVE-2025-53690 to its Known Exploited Vulnerabilities (KEV) catalog on 4 Sep 2025.
• CISA's ransomware flag for this entry is "Unknown": no evidence of ransomware use in the catalog, which is not proof of none.
• The due date CISA sets for the required action is 25 Sep 2025.
• The CVE record was published on 3 Sep 2025, 1 day before it was added to KEV.
• The CVE record carries a CVSS v3.1 base score of 9.0 (Critical), given by its CNA.
• FIRST's EPSS model puts the probability of exploitation in the next 30 days at 60.6% (percentile 99.1), as of 28 Oct 2026.
• CISA's SSVC assessment in the CVE record: exploitation active, automatable no, technical impact total.

Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026. About the data.

Description

Sitecore Products ViewState Deserialization Vulnerability

Deserialization of Untrusted Data vulnerability in Sitecore Experience Manager (XM), Sitecore Experience Platform (XP) allows Code Injection.This issue affects Experience Manager (XM): through 9.0; Experience Platform (XP): through 9.0.

Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.

Weakness

• CWE-502: Deserialization of Untrusted Data

Attack patterns (CAPEC)

• CAPEC-242: Code Injection

CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record and the KEV entry.

Timeline

References

• cloud.google.com
• support.sitecore.com

More exploited Sitecore vulnerabilities

• CVE-2019-9874: Sitecore CMS and Experience Platform (XP) Deserialization Vulnerability (added 26 Mar 2025)
• CVE-2019-9875: Sitecore CMS and Experience Platform (XP) Deserialization Vulnerability (added 26 Mar 2025)
• CVE-2021-42237: Sitecore XP Remote Command Execution Vulnerability (added 25 Mar 2022)