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CVE-2026-20963

Deserialization of Untrusted Data — is CVE-2026-20963real, exploitable, or a false positive? Here's the community ground truth.

Critical · CVSS 9.8EPSS 31.1%CISA KEVCWE-502 · Deserialization of Untrusted Data

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Deserialization of untrusted data in Microsoft Office SharePoint allows an unauthorized attacker to execute code over a network.

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Community ground truth

Community verdict

3 verdicts
Not a real issue

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Community real-world severity: Critical (Critical 3) — CVSS base score 9.8

In line with its CVSS base score.

Field notes & remediation

Verdicts are the quick signal — notes are the evidence and fixes behind them.

  • 0
    Field note · Lin WeiCurated

    Microsoft SharePoint Deserialization of Untrusted Data Vulnerability — Microsoft SharePoint contains a deserialization of untrusted data vulnerability that allows an unauthorized attacker to execute code over a network. Listed in the CISA KEV catalog (added 2026-03-18) — confirmed exploited in the wild, not theoretical. FIRST EPSS puts the chance of exploitation in the next 30 days at ~31%. Treat it as real and prioritize remediation over triage.

  • 0
    Remediation · Nadia PetrovaCurated

    Required action for Microsoft SharePoint: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. CISA set a federal remediation due date of 2026-03-21. After patching, verify the vulnerable path is no longer reachable before closing the finding.

Same weaknessCWE-502 · Deserialization of Untrusted Data.