CVE-2026-50522: Microsoft SharePoint Deserialization of Untrusted Data Vulnerability

Q: How do I fix CVE-2026-50522?

sharepoint server: upgrade to 16.0.19725.20434. Exact commands for each OS are on this page.

Q: Is CVE-2026-50522 being exploited?

Yes. CVE-2026-50522 is on the CISA Known Exploited Vulnerabilities list, so treat it as patch-now.

Q: What does CVE-2026-50522 affect?

CVE-2026-50522 affects sharepoint server. Severity is critical (CVSS 9.8). Deserialization of untrusted data in Microsoft Office SharePoint allows an unauthorized attacker to execute code over a network.

Q: How urgent is CVE-2026-50522?

Priority 99/100. Critical severity; Exploited in the wild (CISA KEV); Public exploit reference; CISA SSVC: automatable with total technical impact; Remotely exploitable, no login, no user action; On your watchlist

Patch now

CRITICAL 9.8EXPLOITEDREMOTEWATCHLISTUPGRADE

CVE-2026-50522 is a critical-severity flaw (CVSS 9.8) affecting sharepoint server, reported as exploited in the wild. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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

Why this priority

Critical severity
Exploited in the wild (CISA KEV)
Public exploit reference
CISA SSVC: automatable with total technical impact
Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	3.0% (top 13%)
CISA exploited list	Yes, fix due 2026-07-25
Weakness	CWE-502
Published	2026-07-14
Last modified	2026-07-23

Publisher (CNA): Microsoft Corporation · Vendor: microsoft

Last updated 2026-07-23 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-07-14 17:17 UTCPublished CVE record published
2026-07-22Exploited Added to the CISA Known Exploited Vulnerabilities list
2026-07-23 15:44 UTCUpdated Record last modified
2026-07-25Deadline CISA due date for US federal agencies to patch

microsoft sharepoint server UPGRADE

Affected: < 16.0.19725.20434 · 2016 · 2019

Fixed in: 16.0.19725.20434

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy sharepoint-server || rpm -q sharepoint-server || sharepoint-server --version

2. UPGRADE to 16.0.19725.20434 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade sharepoint-server

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade sharepoint-server

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Exact fixes by distribution

Fedora 46 · gcl · FIXED · 2.7.1-12.fc46 · FEDORA-2026-ff383a759b · source

sudo dnf upgrade --advisory=FEDORA-2026-ff383a759b

Fedora ELN · mozjs140 · FIXED · 140.13.0-5.eln159 · FEDORA-2026-f7ed0026e0 · source

sudo dnf upgrade --advisory=FEDORA-2026-f7ed0026e0

Microsoft SharePoint Enterprise Server 2016 · KB5002891 · FIXED · 16.0.5561.1001 · KB5002891 · source

Install KB5002891 via Windows Update, then verify: Get-HotFix -Id KB5002891

Microsoft SharePoint Server 2019 · KB5002883 · FIXED · 16.0.10417.20175 · KB5002883 · source

Install KB5002883 via Windows Update, then verify: Get-HotFix -Id KB5002883

Microsoft SharePoint Server Subscription Edition · KB5002882 · FIXED · 16.0.19725.20434 · KB5002882 · source

Install KB5002882 via Windows Update, then verify: Get-HotFix -Id KB5002882

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

GitHub PoC: 4minx/CVE-2026-50522 (44 stars)
GitHub PoC: WismanSec/sharepoint-2026-poc (2 stars)
GitHub PoC: HORKimhab/CVE-2026-50522 (0 stars)

Advisories and coverage

Official advisories

CERT-FR Alerts: Multiples vulnérabilités dans Microsoft Sharepoint (22 juillet 2026) 2026-07-22

Verify at the official source NVD · CVE Program · CISA KEV catalog · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-50522?

sharepoint server: upgrade to 16.0.19725.20434. Exact commands for each OS are on this page.

Is CVE-2026-50522 being exploited?

Yes. CVE-2026-50522 is on the CISA Known Exploited Vulnerabilities list, so treat it as patch-now.

What does CVE-2026-50522 affect?

CVE-2026-50522 affects sharepoint server. Severity is critical (CVSS 9.8). Deserialization of untrusted data in Microsoft Office SharePoint allows an unauthorized attacker to execute code over a network.

How urgent is CVE-2026-50522?

Priority 99/100. Critical severity; Exploited in the wild (CISA KEV); Public exploit reference; CISA SSVC: automatable with total technical impact; Remotely exploitable, no login, no user action; On your watchlist

Software pages

SharePoint vulnerabilities · Microsoft Office vulnerabilities

Related CVEs

CVE-2026-32201 MEDIUM 6.5 EXPLOITED UPGRADE Microsoft SharePoint Server Improper Input Validation Vulnerability
CVE-2026-20945 MEDIUM 4.6 UPGRADE Improper neutralization of input during web page generation ('cross-site scripting') in Microsoft Office Share
CVE-2026-33112 HIGH 8.8 UPGRADE Deserialization of untrusted data in Microsoft Office SharePoint allows an authorized attacker to execute code
CVE-2026-33110 HIGH 8.8 UPGRADE Deserialization of untrusted data in Microsoft Office SharePoint allows an authorized attacker to execute code
CVE-2026-35439 HIGH 8.8 UPGRADE Deserialization of untrusted data in Microsoft Office SharePoint allows an authorized attacker to execute code

References

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