Cyber 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

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 Exploit Public-Facing Application (T1190); 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

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
T1210 Exploitation of Remote Services Lateral Movement
Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.
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-2025-55182Shared CWE-502both on KEV
CVE-2018-1000861Shared CWE-502both on KEV
CVE-2026-45247Shared CWE-502both on KEV
CVE-2026-20963Shared CWE-502both on KEV
CVE-2017-3066Shared 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
prevents

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.

finds

Security testing includes validation of deserialization routines and the use of untrusted data, reducing the likelihood that unsafe object reconstruction will be deployed.

prevents

Requiring vetted libraries, regular updates and SAST before release reduces the likelihood that deserialization logic will accept and act on attacker-controlled serialized objects.

finds

Regular scanning of third-party libraries and timely patching reduce the likelihood that unsafe deserialization vulnerabilities remain active.

none

Mandatory malware scanning of data received over networks or storage media intercepts malicious serialized payloads before they are deserialized by the target application.

References