basicsecurity.net
Proof, not just disclosure.
Threats / Microsoft / CVE-2016-0151
CVE-2016-0151 · EUVD no mirror located · GCVE no mirror located Verified 2026-08-04

Microsoft Client-Server Run-time Subsystem (CSRSS) vulnerability

Microsoft CSRSS mismanages process tokens, allowing local users to gain elevated privileges through a crafted application.

Verdict

Today item, not a backlog item.

A local privilege escalation vulnerability in the Client-Server Run-time Subsystem enables attackers with user-level access to execute code with system privileges. Active exploitation and ransomware deployment have been observed.

CISA KEV Yes · 2022-03-284Ransomware use Flagged4EPSS 0.63195 (verify live)5CVSS 7.8 (CISA)3CISA SSVC Exploitation: active · Automatable: no · Impact: total3
01

Is it exploitable?

— the evidence, ranked above the score
Reported exploitation
1 independent public report of in-the-wild exploitation are cataloged.Distinct reporting sources (vendor, incident response, government); open them for the underlying claims.
cisa.gov ↗Confirmed
Exploited in the wild
Listed in the CISA Known Exploited Vulnerabilities catalog (added 2022-03-28), flagged for known ransomware use.
CISA KEV ↗Confirmed
Probability (EPSS)
EPSS 0.63195 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
CVSS 7.8 (CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H) · Affected: Microsoft, Client-Server Run-time Subsystem (CSRSS). 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-264 Permissions/Privileges/Access Control — weakness family: Authorization / access control.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: 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.
CISA-ADP ↗Reported
Currency of the record
CISA added this to its KEV catalog 2176 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.
WeaknessCWE-264 · Permissions/Privileges/Access ControlAuthorization / access control
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 that exploits token mismanagement in CSRSS to request elevated privileges.
Business
An attacker gains local code execution with system-level permissions on affected endpoints.
2

Keys to the kingdom — privilege/identity takeover narrative 2

Attacker
I execute my application on a compromised system where I already have user-level access.
Business
The vulnerability is triggered, bypassing Windows privilege boundaries and granting administrative control.
3

Lateral reach — past segmentation narrative 3

Attacker
I deploy ransomware or additional malicious payloads using the elevated privileges I have obtained.
Business
Critical systems become compromised, leading to data encryption, operational disruption, and potential financial extortion.
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)
  • 1 reported-exploitation source(s)
  • CVSS 7.8 — CISA-assigned (CVE.org ADP)
  • CISA SSVC triage disposition (CVE.org ADP)
  • CWE weakness mapping (NVD feed — CNA left none)
  • 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.