CVE-2019-9875: Sitecore CMS and Experience Platform (XP) Deserialization Vulnerability
- Is it exploited?
Yes. CISA added it to the Known Exploited Vulnerabilities catalog on , 2,126 days after the CVE record was published.
- How likely is exploitation in the next 30 days?
- 25.4%
EPSS score, percentile 97.9 of all scored records
- How severe?
- 8.8 High
CVSS v3.1 base score, from CISA's enrichment of the record
- What should I do?
CISA deadline . 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?
Not stated. The CVE record gives vendor and product as “n/a” and the version as “unspecified”.
Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of ; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of ; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.
What to do
Required action, set by CISA
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
CISA due date for this action: .
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=KB0038556
- https://nvd.nist.gov/vuln/detail/CVE-2019-9875
Affected products and versions
The CVE record does not name affected products or versions: vendor and product are “n/a” and the version is “unspecified”.
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.
About this vulnerability
Sitecore CMS and Experience Platform (XP) contain a deserialization vulnerability in the Sitecore.Security.AntiCSRF module that allows an authenticated attacker to execute arbitrary code by sending a serialized .NET object in the HTTP POST parameter __CSRFTOKEN.
Summary: CISA's KEV catalog, as of .
- CISA added CVE-2019-9875 to its Known Exploited Vulnerabilities (KEV) catalog on 26 Mar 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 16 Apr 2025.
- The CVE record was published on 31 May 2019, 2,126 days before it was added to KEV.
- The CVE record carries a CVSS v3.1 base score of 8.8 (High), taken from CISA's enrichment of the record.
- FIRST's EPSS model puts the probability of exploitation in the next 30 days at 25.4% (percentile 97.9), 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 ; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of ; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of . About the data.
Description
Deserialization of Untrusted Data in the anti CSRF module in Sitecore through 9.1 allows an authenticated attacker to execute arbitrary code by sending a serialized .NET object in an HTTP POST parameter.
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.
Weakness
- CWE-502: Deserialization of Untrusted Data
CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record and the KEV entry.
Timeline
| Date | Event |
|---|---|
| CVE record published | |
| Added to CISA KEV | |
| CISA due date for the required action | |
| CVE record last updated |
References
More exploited Sitecore vulnerabilities
- CVE-2025-53690: Sitecore Multiple Products Deserialization of Untrusted Data Vulnerability
- CVE-2019-9874: Sitecore CMS and Experience Platform (XP) Deserialization Vulnerability
- CVE-2021-42237: Sitecore XP Remote Command Execution Vulnerability