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CVE-2026-70321· NVD / CVE Program· CNA microsoft

Microsoft SharePoint Remote Code Execution Vulnerability

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

HighCVSS 8.8 · v3.1—No exploit Fix available
Published
Aug 11, 2026
Updated
Sep 29, 2026
EPSS
1.7% · 76th percentile
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Report tools

JSON

Action score

36

Monitor

Low priority for now.

CVSS
35 / 40 · 8.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
1 / 30 · 1.7%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · microsoft
8.8
NVD has not scored this yet; the score shown is the CNA’s.

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

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Affected systems

VendorProduct
microsoftsharepoint server

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • microsoft sharepoint serverbefore 16.0.19725.20522

Versions reported by the vendor

Affected version ranges reported by the assigning authority (microsoft). Independent of NVD's CPE analysis and usually ahead of it.

  • Microsoft Microsoft SharePoint Server Subscription Edition

    • 16.0.0 and later · before 16.0.19725.20522affected

Same product

microsoft: all records

Other highest-scoring records for the same primary product.

  • CVE-2025-53770Microsoft SharePoint Server Remote Code Execution VulnerabilityKEV
    99Now
  • CVE-2023-29357Microsoft SharePoint Server Elevation of Privilege VulnerabilityKEV
    99Now
  • CVE-2025-49704Microsoft SharePoint Remote Code Execution VulnerabilityKEV
    95Now
  • CVE-2026-20963Microsoft SharePoint Remote Code Execution VulnerabilityKEV
    78This week
  • CVE-2026-58644Microsoft SharePoint Remote Code Execution VulnerabilityKEV
    74This week
  • CVE-2024-38094Microsoft SharePoint Remote Code Execution VulnerabilityKEV
    73This week

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Microsoft SharePoint Server Subscription Edition16.0.19725.20522 · KB5002893Microsoft (MSRC)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2025-53770388 days apartMicrosoft SharePoint Server Remote Code Execution VulnerabilityKEV
    99Now
  • CVE-2026-20963210 days apartMicrosoft SharePoint Remote Code Execution VulnerabilityKEV
    78This week
  • CVE-2026-5864428 days apartMicrosoft SharePoint Remote Code Execution VulnerabilityKEV
    74This week
  • CVE-2026-5052228 days apartMicrosoft SharePoint Remote Code Execution VulnerabilityKEV
    70This week
  • CVE-2026-4565981 days apartMicrosoft SharePoint Remote Code Execution VulnerabilityKEV
    66This week
  • CVE-2025-54897336 days apartMicrosoft SharePoint Remote Code Execution Vulnerability
    41Plan

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-502 · Deserialization of Untrusted Data

CVSS vector

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

nvd-secondary

Root cause

Data received over the network is deserialized into the language’s native object format without verifying its source. Code paths inside the object can be triggered during deserialization.

The bug in code

The whole CWE-502 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

python
payload = sock.recv(65536)job = pickle.loads(payload)

Fixed

python
payload = sock.recv(65536)if not hmac.compare_digest(sign(payload), header_sig):    raise PermissionError("invalid signature")job = JobSchema.validate(json.loads(payload))

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Noroxi analysis

No Noroxi analysis for this record yet

We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.

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Change log

  1. Fix✗ → ✓

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References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records