Threats / Sitecore / CVE-2019-9875
CVE-2019-9875
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-08-04
Sitecore CMS and Experience Platform (XP) vulnerability
Sitecore CMS and Experience Platform contain a deserialization vulnerability in the anti-CSRF module allowing authenticated attackers to execute arbitrary code via malicious serialized .NET objects.
Verdict
Today item — known-exploited.
An authenticated attacker can exploit unsafe deserialization of the __CSRFTOKEN parameter to achieve remote code execution on affected Sitecore instances. This vulnerability has been observed in active exploitation.
CISA KEV Yes · 2025-03-264EPSS 0.14154 (verify live)5CVSS 8.8 (CISA)3CISA SSVC Exploitation: active · Automatable: no · Impact: total3
01
Is it exploitable?
— the evidence, ranked above the scoreReported exploitation
2 independent public reports of in-the-wild exploitation are cataloged.Distinct reporting sources (vendor, incident response, government); open them for the underlying claims.
Exploited in the wild
Listed in the CISA Known Exploited Vulnerabilities catalog (added 2025-03-26).
Probability (EPSS)
EPSS 0.14154 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
CVSS 8.8 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H) · Affected: Sitecore, CMS and Experience Platform (XP). Confirm exact fixed builds in the vendor advisory.CVSS — CISA-assigned via the ADP container (CVE.org), version 3.1; the CNA left no metrics, so CISA's own score is used ahead of NVD.
Weakness (CWE)
Mapped to CWE-502 Deserialization of Untrusted Data — weakness family: Injection.CWE assignment from the public NVD record (may be stale); the weakness class drives how the flaw is exploited.
CISA SSVC (triage disposition)
Exploitation: active · Automatable: no · Technical Impact: totalCISA's own stakeholder-specific triage inputs, published in the CVE record (CISA Coordinator role). NOTE: this is CISA's three decision points; the final Act/Attend/Track decision also requires a Mission & Well-being input not published here, so no overall decision is asserted.
Currency of the record
CISA added this to its KEV catalog 2126 days after the CVE record was published.KEV lag = CISA-KEV dateAdded − CVE.org datePublished; a floor on how long the known-exploited flaw sat in the public record before the federal catalog listed it. Severity/weakness here is CNA- or CISA-assigned (current at disclosure), independent of NVD's analysis backlog.
02
Who’s exploiting it?
— attribution turns risk into urgencyAttribution not established
No confirmed (advisory-backed) threat-actor attribution is established for this record. Absence of a named actor is not absence of compromise — see Coverage & confidence.
03
Why it matters
— the attack path, told twice: adversary, then board1
Front door — unauthenticated access narrative 1
Attacker
I craft a malicious serialized .NET object and submit it as the __CSRFTOKEN parameter in an HTTP POST request to a Sitecore instance where I have valid authentication credentials.
Business
An insider or compromised account holder gains the ability to execute arbitrary code with application privileges, potentially leading to data theft, system compromise, or lateral movement within the infrastructure.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I trigger code execution on the server to establish persistence, escalate privileges, or pivot to other systems on the network.
Business
The organization faces potential breach of sensitive customer data, intellectual property, or operational systems, with significant remediation costs and regulatory exposure.
04
What to do
— defensible action- Remediate per the vendor advisory — confirm the fixed build for your version and verify exposure.1
Say it to the boardA vulnerability with this evidence profile is a defensible budget line, not a backlog ticket — fund the change against the proof above.
05