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Threats / Microsoft / CVE-2025-59287
CVE-2025-59287 · EUVD no mirror located · GCVE no mirror located Verified 2026-06-22

Microsoft Windows vulnerability

Microsoft Windows Server Update Service (WSUS) contains a deserialization vulnerability allowing remote code execution. The flaw has been exploited in the wild.

Verdict

Today item — known-exploited.

A deserialization flaw in WSUS enables unauthenticated remote code execution. Active exploitation in the wild combined with high EPSS score indicates immediate risk to Windows Server environments relying on WSUS for patch management.

CISA KEV Yes · 2025-10-243EPSS 0.99962 (verify live)4Exploit Weaponized · public PoC5
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
206 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 2025-10-24).
CISA KEV ↗Confirmed
Probability (EPSS)
EPSS 0.99962 — 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-502 Deserialization of Untrusted Data — weakness family: Injection.CWE assignment from the public NVD record; the weakness class drives how the flaw is exploited.
NVD ↗Reported
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 serialized object and send it to an exposed WSUS endpoint to trigger deserialization of untrusted data.
Business
Attackers gain arbitrary code execution on Windows Server infrastructure, potentially compromising patch management systems and enabling lateral movement across enterprise networks.
2

Keys to the kingdom — privilege/identity takeover narrative 2

Attacker
I execute arbitrary commands with the privileges of the WSUS service account on the compromised server.
Business
Operational continuity is disrupted as WSUS infrastructure is compromised, blocking legitimate security updates and exposing the organization to secondary attacks.
3

Lateral reach — past segmentation narrative 3

Attacker
I use the compromised WSUS server to distribute malicious updates or maintain persistent access across dependent systems.
Business
The integrity of the patch management supply chain is broken, potentially affecting hundreds of client systems and creating cascading security failures.
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)
  • EPSS probability (FIRST)
  • Weaponized exploit available (VulnCheck)
  • 206 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.