Security Digest · Vulnerability record · Known exploited
CVE-2019-9875: Sitecore CMS and Experience Platform (XP) Deserialization Vulnerability
Exploited in the wild (CISA KEV). 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.
CISA KEV · added 2025-03-26 CVSS 8.8 High EPSS 13.8% · p97
Should you act?
Exploited: patch now if you run it
CISA has confirmed exploitation in the wild. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.
- Yes, if you run Sitecore CMS and Experience Platform (XP). CISA added this CVE to its Known Exploited Vulnerabilities catalog on 2025-03-26, which means there is reliable evidence of exploitation in the wild. US federal agencies must remediate by 2025-04-16; treat that as the outer limit, not the target.
- EPSS 13.8%, percentile 97: FIRST’s model estimates a 13.8% chance of exploitation activity in the next 30 days, higher than 97% of all scored CVEs (very high). EPSS is a probability, not a verdict.
- Needs an account (low (any account)). Exposure depends on who can log in.
What it is
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.
CISA’s summary
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.
Weakness type: CWE-502.
Product: Sitecore CMS and Experience Platform (XP) · Assigned by: mitre · Published: 2019-05-31
Affected and fixed versions
| Vendor | Product | Affected versions (per CVE record) |
|---|---|---|
| n/a | n/a | see vendor advisory |
Severity scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| CISA-ADP | 3.1 | 8.8 High | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
- Attack vector: network (remotely reachable)
- Attack complexity: low
- Privileges required: low (any account)
- User interaction: none
- Scope: unchanged
CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.
Exploitation and urgency
- CISA KEV: added 2025-03-26; federal due date 2025-04-16. Known ransomware use: Unknown.
- CISA required action: 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 SSVC assessment: exploitation active, automatable no, technical impact total.
- FIRST EPSS (model of 2026-10-21): 13.79% probability of exploitation activity in the next 30 days; percentile 97.
Timeline
- — CVE record published by mitre
- — Added to CISA’s Known Exploited Vulnerabilities catalog
- — CISA remediation deadline for US federal agencies
- — CVE record last updated
Sources and references
Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.
Vendor and project advisories, patches
- Listed in CISA KEV notes (support.sitecore.com) support.sitecore.com
Vulnerability records
- CVE.org record CVE-2019-9875 cve.org
- NVD entry CVE-2019-9875 nvd.nist.gov
Government
Other references from the CVE record and advisory
- dev.sitecore.net dev.sitecore.net
- synacktiv.com synacktiv.com
- synacktiv.com synacktiv.com
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