CyberSecBulletin
CVE-2019-9874Exploited in the wildNVD status: Analyzed

Sitecore CMS and Experience Platform (XP) Deserialization

Published Updated By the CyberSecBulletin desk

CVE-2019-9874 is a critical-severity deserialization of untrusted data vulnerability in CMS from Sitecore, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected CMS versions: 7.0 through 7.2. The record does not name a fixed version, so check the vendor advisory. CISA added it to the Known Exploited Vulnerabilities catalogue on March 26, 2025, which means attacks have been observed in the wild.

Patch now

Attackers are already exploiting this vulnerability, according to CISA.

What to do

  1. Check which version of CMS you run against the affected versions below, and install the vendor's latest release.
  2. CISA's 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.
  3. Read the advisory on dev.sitecore.net for workarounds and exact fixed builds.
  4. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
SitecoreCMS7.0 through 7.2Not stated
SitecoreExperience Platform7.5 through 8.2Not stated

Version data comes from NVD's product matching. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 3.19.8CriticalNVD
CVSS 3.19.8CriticalCISA (ADP)
CVSS 2.07.5HighNVD

Official description

Deserialization of Untrusted Data in the Sitecore.Security.AntiCSRF (aka anti CSRF) module in Sitecore CMS 7.0 to 7.2 and Sitecore XP 7.5 to 8.2 allows an unauthenticated attacker to execute arbitrary code by sending a serialized .NET object in the HTTP POST parameter __CSRFTOKEN.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Deserialization of Untrusted Data

The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.

How developers prevent this class of flaw

  • If available, use the signing/sealing features of the programming language to assure that deserialized data has not been tainted. For example, a hash-based message authentication code (HMAC) could be used to ensure that data has not been modified.
  • When deserializing data, populate a new object rather than just deserializing. The result is that the data flows through safe input validation and that the functions are safe.
  • Explicitly define a final object() to prevent deserialization.

More Deserialization of Untrusted Data vulnerabilities (CWE-502)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: active, automatable: yes, technical impact: total).
  3. Added to CISA's Known Exploited Vulnerabilities catalogue.
  4. Deadline for US federal agencies to remediate, set by CISA.
  5. Record last changed materially (score, affected products, status or references).

References

Patches and release notes

Third-party and government advisories

Other vulnerabilities in CMS

All CMS vulnerabilities

Recent Deserialization of Untrusted Data vulnerabilities

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