CVE-2026-65815: Deserialization of untrusted data in Microsoft Dynamics 365 (on-premises) allows an authorized attacker to exe

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HIGH 8.8WATCHLISTUPGRADE

CVE-2026-65815 is a high-severity flaw (CVSS 8.8) affecting dynamics 365. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Deserialization of untrusted data in Microsoft Dynamics 365 (on-premises) allows an authorized attacker to execute code over a network.

Why this priority

High severity
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	8.8 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	1.7% (top 23%)
CISA exploited list	No
Weakness	CWE-502
Published	2026-08-11
Last modified	2026-10-23

Publisher (CNA): Microsoft Corporation · Vendor: microsoft

Last updated 2026-10-23 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-08-11 17:19 UTCPublished CVE record published
2026-10-23 19:10 UTCUpdated Record last modified

microsoft dynamics 365 UPGRADE

Affected: >= 9.1 and < 9.1.47.06

Fixed in: 9.1.47.06

Safe to downgrade to: a release before 9.1

1. Check installed version

apt-cache policy dynamics-365 || rpm -q dynamics-365 || dynamics-365 --version

2. UPGRADE to 9.1.47.06 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade dynamics-365

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade dynamics-365

Note

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

3. If no update is available yet, DOWNGRADE to a release before 9.1 (Debian / Ubuntu)

apt-cache madison dynamics-365 sudo apt install dynamics-365=<VERSION_BEFORE_9.1> sudo apt-mark hold dynamics-365

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list dynamics-365 sudo dnf downgrade dynamics-365-<VERSION_BEFORE_9.1> sudo dnf versionlock add dynamics-365

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Exact fixes by distribution

Fedora 46 · diffoscope · FIXED · 335-1.fc46 · FEDORA-2026-e4c4cc0856 · source

sudo dnf upgrade --advisory=FEDORA-2026-e4c4cc0856

Verify at the official source NVD · CVE Program · 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-2026-65815?

dynamics 365: upgrade to 9.1.47.06. Exact commands for each OS are on this page.

Is CVE-2026-65815 being exploited?

CVE-2026-65815 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-65815 affect?

CVE-2026-65815 affects dynamics 365. Severity is high (CVSS 8.8). Deserialization of untrusted data in Microsoft Dynamics 365 (on-premises) allows an authorized attacker to execute code over a network.

How urgent is CVE-2026-65815?

Priority 55/100. High severity; On your watchlist

Related CVEs

CVE-2026-66301 MEDIUM 6.5 UPGRADE Exposure of sensitive information to an unauthorized actor in Microsoft Dynamics 365 (on-premises) allows an a

References

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