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CVE-2026-63520

HIGH 8.1 PoC CATALOGUED ALL-YEARS

Published 2026-08-11 · Last modified 2026-10-21 · microsoft · NVD: Analyzed

Improper input validation in Microsoft Office SharePoint allows an unauthorized attacker to execute code over a network.

REPORTED EXPLOITATION

VulnCheck KEV reports exploitation for this CVE. These are source-specific reports; review the details and vendor guidance below.

Exploitation likelihood

1.0%chance of exploitation in 30 days · 61st percentile

○ In CISA KEV● Catalogued PoC◆ SSVC: exploitation none, automatable no

Impact if exploited

8.1CVSS 3.1 · HIGH · CNA

  • ConfidentialityHigh
  • IntegrityHigh
  • AvailabilityHigh

What an attacker needs

  • ✓Access: Reachable over the network — no local access needed
  • ✓Privileges: No account or privileges required
  • ✓User interaction: No user interaction needed
  • ⚠Complexity: Needs a race window or specific setup

✓ lowers the bar for an attacker · ⚠ raises it

Proof of concept

Public PoC or exploit resources are catalogued below.

Listed by the named source; Vulnpedia has not tested these resources.

PoC data: JSON

Resource commands

curl -s https://vulnpedia.com/cve/CVE-2026-63520/poc.jsonMachine-readable PoC index for this CVE (for automation).

Search for new PoCs

Search GitHub now — results may be empty or unverified.

Tracked sources are checked weekly for the full archive, including PoCs published after the original disclosure. A later release appears after a tracked source lists it and a refresh succeeds.

Data snapshot:

Affected

Vendors Microsoft

Products Microsoft Sharepoint Enterprise Server 2016 Microsoft Sharepoint Server 2019 Microsoft Sharepoint Server Subscription Edition Sharepoint Server

Weakness (CWE)

  • CWE-20: : Improper Input Validation

CVSS vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C

References and research data (JSON)

Unverified PoC candidates

Catalogue matches for further research. These repositories have not been validated as working exploits.

1 candidate

Additional exploitation reports

Source-specific reports, separate from CISA KEV. Repeated observations from one source are not independent confirmations.

  • VulnCheck KEV · 2026-08-25T00:00:00Z

    Source guidance: Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.

    Source ransomware assessment: Unknown

    VulnCheck KEV · CVE-2026-63520 · Updated 2026-08-25T00:00:00Z
  • VulnCheck KEV · 2026-08-25T00:00:00ZVulnCheck KEV · CVE-2026-63520
  • VulnCheck KEV · 2026-08-26T00:00:00ZVulnCheck KEV · CVE-2026-63520

Known Affected Software Configurations

VendorProductVersion range
MicrosoftSharepoint Server< 16.0.19725.20522
MicrosoftSharepoint Server2016
MicrosoftSharepoint Server2019

All CVSS metrics

  • HIGH 8.1 v3.1 · CNA Primary
    CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
  • HIGH 8.1 v3.1 · NVD Secondary
    CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

References

Patches & mitigations

Advisories

Technical & other

Sources: NVD · CVE.org · All sources and attribution · EPSS