CVE-2026-20963
Microsoft SharePoint: Deserialization of Untrusted Data
As of , CVE-2026-20963 in Microsoft SharePoint is on CISA's list of exploited vulnerabilities: CISA listed it on . Our patch-first group: Patch soon.
- Exploited
- Yes: CISA listed it on 18 March 2026
- US federal deadline
- 21 March 20263 days after CISA listed it. US federal civilian agencies must fix it by then.
- Used in ransomware campaigns
- Not known to CISA
- EPSS score
- 0.30Higher than 98% of the CVEs EPSS scores. EPSS estimates the chance of exploitation activity in the next 30 days.
- Public exploit
- None foundNeither Metasploit nor Exploit-DB lists one.
- Fix
- Vendor advice: msrc.microsoft.comLinks below, from CISA's entry.
What CISA says to do
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's required action
What the flaw is
Microsoft SharePoint contains a deserialization of untrusted data vulnerability that allows an unauthorized attacker to execute code over a network.
CISA's description
Deserialization of untrusted data in Microsoft Office SharePoint allows an unauthorized attacker to execute code over a network.
The CVE record's description, from microsoft
- CVE published
- 13 January 2026
- Assigned by
- microsoft
- CVSS
- 9.8 Critical (CVSS 3.1, from the CNA)
- CWE-502
- Deserialization of Untrusted Data
- CISA SSVC, exploitation
- active
- CISA SSVC, automatable
- yes
- CISA SSVC, technical impact
- total
Timeline
- The CVE record was published.
- CISA added it to its list of exploited vulnerabilities.
- The US federal deadline to fix it.
SharePoint: other exploited entries
| Vulnerability | Product | Our group | Listed | Deadline | EPSS |
|---|---|---|---|---|---|
| CVE-2026-55040Weak Authentication | Microsoft SharePoint | Patch nowForensic triage required by CISA | 0.70 | ||
| CVE-2026-58644Deserialization of Untrusted Data | Microsoft SharePoint | Patch nowForensic triage required by CISA | 0.16 | ||
| CVE-2026-50522Deserialization of Untrusted Data | Microsoft SharePoint | Patch nowForensic triage required by CISA | 0.03 | ||
| CVE-2026-65660Code Injection | Microsoft SharePoint | Patch nowForensic triage required by CISA; listed in the last 14 days | 0.02 | ||
| CVE-2025-49704Code Injection | Microsoft SharePoint | Patch this weekRansomware use; Metasploit module; EPSS 0.99 | 0.99 | ||
| CVE-2025-49706Improper Authentication | Microsoft SharePoint | Patch this weekRansomware use; Metasploit module; EPSS 0.99 | 0.99 | ||
| CVE-2025-53770Deserialization of Untrusted Data | Microsoft SharePoint | Patch this weekRansomware use; Metasploit module; EPSS 0.99 | 0.99 | ||
| CVE-2019-0604Remote Code Execution | Microsoft SharePoint | Patch this weekRansomware use; EPSS 0.99 | 0.99 | ||
| CVE-2024-38094Deserialization | Microsoft SharePoint | Patch this weekRansomware use; EPSS 0.51 | 0.51 |
Read further
- CVE recordcve.org
- NVD entrynvd.nist.gov
- CISA's catalogcisa.gov
- EPSS for this CVEapi.first.org