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Threats / Microsoft / CVE-2019-0604
CVE-2019-0604 · EUVD no mirror located · GCVE no mirror located Verified 2026-08-04

Microsoft SharePoint vulnerability

Microsoft SharePoint fails to validate application package source markup, allowing remote code execution in the SharePoint application pool and farm account context.

Verdict

Today item, not a backlog item.

An unauthenticated or low-privileged attacker can exploit improper input validation in SharePoint application packages to achieve remote code execution with elevated privileges, enabling full server compromise and lateral movement within the farm.

CISA KEV Yes · 2021-11-034Ransomware use Flagged4EPSS 0.99825 (verify live)5Exploit Weaponized · public PoC6CVSS 9.8 (CISA)3CISA SSVC Exploitation: active · Automatable: yes · Impact: total3
01

Is it exploitable?

— the evidence, ranked above the score
Exploit available
Fully weaponized — public exploit code is cataloged for this vulnerability.We link the existence of the exploit; we do not host or redistribute payloads.
Reported exploitation
34 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 2021-11-03), flagged for known ransomware use.
CISA KEV ↗Confirmed
Probability (EPSS)
EPSS 0.99825 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
CVSS 9.8 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H) · Affected: Microsoft, SharePoint. 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.
CISA-ADP ↗Reported
Weakness (CWE)
Mapped to CWE-20 Improper Input Validation.CWE assignment from the public NVD record (may be stale); the weakness class drives how the flaw is exploited.
NVD ↗Reported
CISA SSVC (triage disposition)
Exploitation: active · Automatable: yes · 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.
CISA-ADP ↗Reported
Currency of the record
CISA added this to its KEV catalog 973 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 urgency
Attribution 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 board
1

Front door — unauthenticated access narrative 1

Attacker
I craft a malicious application package with invalid or malicious source markup that bypasses validation checks.
Business
Attackers gain initial foothold to deploy ransomware or establish persistent access across SharePoint infrastructure.
2

Keys to the kingdom — privilege/identity takeover narrative 2

Attacker
I upload or deploy the crafted package to a vulnerable SharePoint server.
Business
The attack surface includes any organization using SharePoint, with no patch required for exploitation in unpatched systems.
3

Lateral reach — past segmentation narrative 3

Attacker
I execute arbitrary code within the SharePoint application pool and farm account security context.
Business
Attackers inherit the privileges of the SharePoint service account, typically a high-value target with broad farm permissions.
4

Data at risk — exfiltration narrative 4

Attacker
I move laterally to other servers in the SharePoint farm and connected infrastructure using compromised credentials.
Business
Entire SharePoint deployments and dependent systems become compromised, enabling data exfiltration and operational disruption.
5

Lights out — disruption & extortion narrative 5

Attacker
I deploy ransomware or maintain persistent backdoor access for long-term exploitation.
Business
Organizations face extended downtime, data loss, ransom demands, and regulatory compliance violations affecting business continuity.
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

Coverage & confidence

— what we know, and what we don’t

Established (cited)

  • KEV listing (CISA)
  • Ransomware-use flag (CISA)
  • EPSS probability (FIRST)
  • Weaponized exploit available (VulnCheck)
  • 34 reported-exploitation source(s)
  • CVSS 9.8 — CISA-assigned (CVE.org ADP)
  • CISA SSVC triage disposition (CVE.org ADP)
  • CWE weakness mapping (NVD feed — CNA left none)
  • Public exploit availability
  • Catalogued by microsoft (CNA)
  • Coverage gaps — stated, not hidden

  • No EUVD / GCVE mirror in feed — single-authority dependency for the identifier.
  • EPSS & exposure are time-varying; verify live at the source.
  • Threat-actor attribution not established from feed data — absence of a name is not absence of compromise.
  • No finder/reporter credit recorded in the public CVE entry — the work behind this find is unattributed.
  • Disclosure & credit2
    Catalogued by microsoftCNA
    Credited with finding itNo finder named in the public CVE record — the work behind this find is unattributed.