Security Resilience

CVE-2019-9875

RCE in Sitecore Cms ≤ 9.1

CISA KEVActive ExploitationEUVD ExploitedPublic PoCRCEDeserialization
Published
31 May 2019
Modified
07 November 2025
KEV Added
26 March 2025
Patch / advisory
CVSS Score v3.1 8.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.14 96th percentile
Risk Priority 90 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2019-9875 is a high-severity Deserialization of Untrusted Data (CWE-502) vulnerability in Sitecore Cms. Its CVSS base score is 8.8 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Junk Data (T1001.001); ranked in the top 4% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog; a public proof-of-concept is referenced.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

CVE-2019-9875 is a deserialization of untrusted data vulnerability (CWE-502) affecting the anti-CSRF module in Sitecore versions through 9.1. The flaw permits an attacker to supply a malicious serialized .NET object that is processed without sufficient validation, leading to arbitrary code execution on the server.

An authenticated attacker with low privileges can exploit the issue over the network by submitting the crafted object inside an HTTP POST parameter. Successful exploitation yields full control over the application, resulting in high impact to confidentiality, integrity, and availability as reflected in the CVSS 8.8 score.

Sitecore has published updates through its official Downloads portal, while Synacktiv has released a detailed advisory and technical PDF describing the flaw and recommended remediation steps.

No information on observed in-the-wild exploitation is provided in the source references.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

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.

CWE(s)
KEV Date Added
26 March 2025

Related Threats

MITRE ATT&CK Enterprise Techniques

T1001.001 Junk Data Command And Control
Adversaries may add junk data to protocols used for command and control to make detection more difficult.
T1001.003 Protocol or Service Impersonation Command And Control
Adversaries may impersonate legitimate protocols or web service traffic to disguise command and control activity and thwart analysis efforts.
T1003.001 LSASS Memory Credential Access
Adversaries may attempt to access credential material stored in the process memory of the Local Security Authority Subsystem Service (LSASS).
T1003.007 Proc Filesystem Credential Access
Adversaries may gather credentials from the proc filesystem or `/proc`.
T1005 Data from Local System Collection
Adversaries may search local system sources, such as file systems, configuration files, local databases, virtual machine files, or process memory, to find files of interest and sensitive data prior to Exfiltration.
T1006 Direct Volume Access Stealth
Adversaries may directly access a volume to bypass file access controls and file system monitoring.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2019-9874Same product: Sitecore Cmsboth on KEV
CVE-2025-53690Same vendor: Sitecoreboth on KEV
CVE-2021-42237Same vendor: Sitecoreboth on KEV
CVE-2023-27068Same vendor: Sitecore
CVE-2025-53691Same vendor: Sitecore
CVE-2025-23006Shared CWE-502both on KEV
CVE-2015-7450Shared CWE-502both on KEV
CVE-2019-15271Shared CWE-502both on KEV
CVE-2026-63077Shared CWE-502both on KEV
CVE-2021-23758Shared CWE-502both on KEV

Affected Assets

sitecore
cms
≤ 9.1

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-502

Penetration testing supplies malicious serialized objects, detecting unsafe deserialization and supporting corrective actions.

addresses: CWE-502

Evaluation of untrusted data handling (deserialization testing) reveals unsafe processing, which the required remediation process addresses.

addresses: CWE-502

Untrusted serialized data can be deserialized and observed inside the chamber, blocking gadget-chain exploitation outside the sandbox.

addresses: CWE-502

Validates or rejects untrusted serialized data before deserialization occurs.

addresses: CWE-502

Identifies and blocks malicious code introduced through deserialization of untrusted data at system boundaries.

addresses: CWE-502

Integrity verification of serialized information can detect tampering before deserialization occurs.

addresses: CWE-502

Provenance of associated data allows detection of untrusted sources before deserialization or processing occurs.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-02 none match
blocks

PR.PS-02 addresses only post-deployment updates/patching and cannot prevent introduction of unsafe deserialization code, yet it can remediate some instances when the flaw exists in outdated libraries or components.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

removes
removes
removes
removes
removes

References