# CVE-2026-123390

Authenticated deserialization RCE in Microsoft SharePoint

- Page: https://www.vulneraibility.com/cve/CVE-2026-123390
- CVSS: 8.8
- Known exploited: not in CISA KEV as of our last sync
- EPSS: 1.70% (percentile 77.4)
- CISA SSVC: exploitation none, automatable no, technical impact total (assessed 2026-11-10)
- Weakness: CWE-502
- Published: 2026-11-10

## Affected versions

- Microsoft Microsoft SharePoint Server Subscription Edition: affected >= 16.0.0 and < 16.0.20326.20136

A version outside these ranges is not a statement that it is unaffected.

## Impact

Authenticated remote code execution via deserialization; attacker with SharePoint access can execute arbitrary code on the server.

## Action

Immediate action required

## Recommendation

Apply Microsoft security updates immediately; restrict SharePoint access and monitor logs.

## References

- [patch] https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-123390

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Summary, impact and action are written by the vulneraibility.com AI analysis pipeline from the CVE record, NVD, CISA and FIRST data; verify against the references.