Threats / Microsoft / CVE-2020-1147
CVE-2020-1147
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-08-04
Microsoft .NET Framework, SharePoint, Visual Studio vulnerability
Microsoft .NET Framework, SharePoint, and Visual Studio contain an XML deserialization remote code execution vulnerability that fails to validate source markup, allowing attackers to execute arbitrary code in the deserialization process con
Verdict
Today item — known-exploited.
This vulnerability enables unauthenticated remote code execution through malicious XML input. The high EPSS score and confirmed wild exploitation indicate active abuse. Organizations must prioritize patching affected Microsoft products immediately.
CISA KEV Yes · 2021-11-034EPSS 0.93966 (verify live)5CVSS 7.8 (CISA)3CISA SSVC Exploitation: active · Automatable: no · Impact: total3Exploit Weaponized · public exploit · Metasploit module9
01
Is it exploitable?
— the evidence, ranked above the scoreReported exploitation
2 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).
Probability (EPSS)
EPSS 0.93966 — 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, .NET Framework, SharePoint, Visual Studio. 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 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.
Currency of the record
CISA added this to its KEV catalog 477 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.
Public exploit available
Public exploit tooling is catalogued for this CVE (a functional/weaponized public exploit). Catalog entries: Metasploit module. We link the catalog page(s) only — no payload or code is hosted or restated here.Link, never host — the catalog page is the source; basicsecurity.net does not redistribute payloads.
02
Who’s exploiting it?
— attribution turns risk into urgencyAttribution 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 board1
Front door — unauthenticated access narrative 1
Attacker
I craft malicious XML content designed to exploit unsafe deserialization in the target application.
Business
Attackers gain code execution within the application process, enabling full system compromise and data exfiltration.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I deliver the XML payload through application input vectors such as file uploads, web requests, or document processing.
Business
The organization loses control of affected servers and workstations, with potential lateral movement across the network.
3
Lateral reach — past segmentation narrative 3
Attacker
I establish persistence and escalate privileges to maintain long-term access to compromised infrastructure.
Business
Incident response costs, operational downtime, and regulatory penalties accumulate as the breach scope expands.
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