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Threats / Microsoft / CVE-2019-1253
CVE-2019-1253 · EUVD no mirror located · GCVE no mirror located Verified 2026-06-22

Microsoft Windows vulnerability

A privilege escalation vulnerability in Windows AppX Deployment Server improperly handles junctions, allowing attackers to gain elevated privileges on affected systems.

Verdict

Today item, not a backlog item.

This CWE-59 symlink/junction handling flaw enables local privilege escalation. Exploitation in the wild and association with ransomware campaigns indicate active abuse for system compromise and lateral movement.

CISA KEV Yes · 2022-03-153Ransomware use Flagged3EPSS 0.11616 (verify live)4Exploit Public PoC5
01

Is it exploitable?

— the evidence, ranked above the score
Exploit available
Public proof-of-concept exploit code is cataloged for this vulnerability.We link the existence of the exploit; we do not host or redistribute payloads.
Reported exploitation
3 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 2022-03-15), flagged for known ransomware use.
CISA KEV ↗Confirmed
Probability (EPSS)
EPSS 0.11616 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
Affected: Microsoft, Windows. Confirm exact fixed builds in the vendor advisory.
NVD ↗Reported
Weakness (CWE)
Mapped to CWE-59 Link Following — weakness family: Path traversal / file.CWE assignment from the public NVD record; the weakness class drives how the flaw is exploited.
NVD ↗Reported
WeaknessCWE-59 · Link FollowingPath traversal / file
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 junction point targeting the AppX Deployment Server's file operations to redirect privileged writes.
Business
Attacker gains SYSTEM-level code execution on the endpoint, bypassing user-mode security boundaries.
2

Keys to the kingdom — privilege/identity takeover narrative 2

Attacker
I use elevated privileges to install malware, disable security controls, or establish persistence mechanisms.
Business
Ransomware operators deploy encryption payloads or data exfiltration tools across the network with administrative rights.
3

Lateral reach — past segmentation narrative 3

Attacker
I move laterally to domain-joined systems or critical infrastructure using compromised credentials and elevated access.
Business
Organizational systems become encrypted or data is stolen; recovery costs and downtime escalate significantly.
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)
  • Public PoC available (VulnCheck)
  • 3 reported-exploitation source(s)
  • CWE weakness mapping (NVD)
  • 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.