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Threats / Microsoft / CVE-2012-1856
CVE-2012-1856 · EUVD no mirror located · GCVE no mirror located Verified 2026-06-22

Microsoft Office vulnerability

TabStrip ActiveX control in Microsoft Office Common Controls allows remote code execution through crafted documents or web pages via system-state corruption.

Verdict

Today item — known-exploited.

Remote attackers can execute arbitrary code by delivering malicious Office documents or hosting crafted web pages that exploit the TabStrip ActiveX control, leading to complete system compromise.

CISA KEV Yes · 2022-03-033EPSS 0.72119 (verify live)4
01

Is it exploitable?

— the evidence, ranked above the score
Reported exploitation
8 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 2022-03-03).
CISA KEV ↗Confirmed
Probability (EPSS)
EPSS 0.72119 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
Affected: Microsoft, Office. Confirm exact fixed builds in the vendor advisory.
NVD ↗Reported
Weakness (CWE)
Mapped to CWE-94 Code Injection — weakness family: Injection.CWE assignment from the public NVD record; the weakness class drives how the flaw is exploited.
NVD ↗Reported
WeaknessCWE-94 · Code InjectionInjection
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 Office document or web page containing specially formed TabStrip ActiveX control parameters.
Business
End users face risk of infection when opening untrusted documents or visiting compromised websites.
2

Keys to the kingdom — privilege/identity takeover narrative 2

Attacker
I deliver the malicious content via email, file sharing, or web hosting to target users.
Business
Attack surface expands across email and web channels, increasing organizational exposure.
3

Lateral reach — past segmentation narrative 3

Attacker
I trigger system-state corruption in the ActiveX control when the document is opened or page is rendered.
Business
Vulnerable systems execute my arbitrary code with user privileges.
4

Data at risk — exfiltration narrative 4

Attacker
I gain code execution and establish persistence or exfiltrate sensitive data.
Business
Confidentiality, integrity, and availability of affected systems are compromised.
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)
  • 8 reported-exploitation source(s)
  • CWE weakness mapping (NVD)
  • 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.