CVE-2026-66816

Microsoft SQL Server Security Feature Bypass Vulnerability

Products / packages Microsoft SQL Server 2022 (CU 26) · Microsoft SQL Server 2022 (GDR) · Microsoft SQL Server 2025 (CU8) · 1 more

Published 08/09/2026, 17:14:27 UTC

Severity and exploitation

Not in CISA KEV

KEV coverage does not rule out exploitation.

KEV checked 05/11/2026, 08:00:30 UTC

microsoft · CVSS:3.1 · 6.5

Assessment vector

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

Severity

medium6.5

CVSS measures technical severity, not the likelihood of an attack.

Known exploitation

Not listed in the checked CISA KEV catalog

Absence from CISA KEV does not rule out attacks.

Public exploit

Not established by this record

Missing evidence does not mean no public exploit exists.

Remediation

Fix status not established

No structured fix or guidance is available here. Check the latest publisher advisory.

What this means

Microsoft SQL Server has a security feature bypass vulnerability due to insufficient logging, allowing an authorized attacker to bypass a security feature over a network, affecting versions 16.0.0.0 to 16.0.4275.2 and 17.0.0.0 to 17.0.4085.5. The vulnerability is identified as CWE-778.

Summarized by @cf/meta/llama-3.3-70b-instruct-fp8-fast. Verify details against the original sources.

Attack conditions

No attack-condition excerpt has been identified here. Review the full source description and references for authentication, network access, and configuration requirements.

Review supporting sources →

Affected versions

Check the exact model, release, and any platform requirements against your installation.

Microsoft · microsoft

Microsoft SQL Server 2022 (CU 26)

1 range

microsoft version evidence

Platforms: x64-based Systems

Check a product version

Compare with this publisher’s ranges. This does not inspect your installation.

affected

16.0.0.0 → before 16.0.4275.2

custom versions

Other versions: unknown

Microsoft · microsoft

Microsoft SQL Server 2022 (GDR)

1 range

microsoft version evidence

Platforms: x64-based Systems

Check a product version

Compare with this publisher’s ranges. This does not inspect your installation.

affected

16.0.0 → before 16.0.1200.5

custom versions

Other versions: unknown

Microsoft · microsoft

Microsoft SQL Server 2025 (CU8)

1 range

microsoft version evidence

Platforms: x64-based Systems

Check a product version

Compare with this publisher’s ranges. This does not inspect your installation.

affected

17.0.0.0 → before 17.0.4085.5

custom versions

Other versions: unknown

Microsoft · microsoft

Microsoft SQL Server 2025 for x64-based Systems (GDR)

1 range

microsoft version evidence

Platforms: x64-based Systems

Check a product version

Compare with this publisher’s ranges. This does not inspect your installation.

affected

17.0.1050.2 → before 17.0.1135.8

custom versions

Other versions: unknown

Automatic dependency matching is unavailable for this record. Use the product evidence and publisher’s instructions to check your installation.

What to do

Compare your installed product and version with the affected versions above. A matching product name alone does not confirm exposure.

No structured fix or remediation guidance is available here. Check the full source description and vendor’s latest advisory for a patch or workaround; do not assume another version is safe.

cve.new guidance unless attributed to a publisher. This page does not inspect your installation.

Public exploit evidence

No public exploit reference is identified in the imported evidence. This is not a claim that no exploit exists.

Original source description

Read the full publisher description

Insufficient logging in SQL Server allows an authorized attacker to bypass a security feature over a network.

References

1 sources

msrc.microsoft.com/update-guide/vulnerability/CVE-2026-66816

Vendor advisorymicrosoft

Inside the record

Evidence available

Package identity · not supplied

Version evidence

Remediation guidance · not supplied

Weakness classification

Additional publishers

Describes the evidence in this view, not whether the product is safe.

Original records

CVE-2026-66816

View the latest unmodified CVE JSON from the official source. It may be newer than this imported page.

cve.new JSON →

Underlying weaknesses

The source’s classification of what caused the vulnerability.

CWE-778 ↗

CWE-778: Insufficient Logging

microsoft

Environment requirements

These conditions apply together as specified by the publisher. A matching product name alone does not establish exposure.

microsoft · platform conditions

Any condition may hold

Vulnerable product

cpe:2.3:a:microsoft:sql_server_2022:*:*:*:*:*:*:x64:*

From (inclusive): 16.0.0

After:

Through (inclusive):

Before: 16.0.1200.5

Vulnerable product

cpe:2.3:a:microsoft:sql_server_2025:*:*:*:*:*:*:x64:*

From (inclusive): 17.0.1050.2

After:

Through (inclusive):

Before: 17.0.1135.8

Vulnerable product

cpe:2.3:a:microsoft:sql_server_2025:*:*:*:*:*:*:x64:*

From (inclusive): 17.0.0.0

After:

Through (inclusive):

Before: 17.0.4085.5

Vulnerable product

cpe:2.3:a:microsoft:sql_server_2022:*:*:*:*:*:*:x64:*

From (inclusive): 16.0.0.0

After:

Through (inclusive):

Before: 16.0.4275.2

Original applicability statements

[
  {
    "nodes": [
      {
        "operator": "OR",
        "negate": false,
        "cpeMatch": [
          {
            "vulnerable": true,
            "criteria": "cpe:2.3:a:microsoft:sql_server_2022:*:*:*:*:*:*:x64:*",
            "versionStartIncluding": "16.0.0",
            "versionEndExcluding": "16.0.1200.5"
          },
          {
            "vulnerable": true,
            "criteria": "cpe:2.3:a:microsoft:sql_server_2025:*:*:*:*:*:*:x64:*",
            "versionStartIncluding": "17.0.1050.2",
            "versionEndExcluding": "17.0.1135.8"
          },
          {
            "vulnerable": true,
            "criteria": "cpe:2.3:a:microsoft:sql_server_2025:*:*:*:*:*:*:x64:*",
            "versionStartIncluding": "17.0.0.0",
            "versionEndExcluding": "17.0.4085.5"
          },
          {
            "vulnerable": true,
            "criteria": "cpe:2.3:a:microsoft:sql_server_2022:*:*:*:*:*:*:x64:*",
            "versionStartIncluding": "16.0.0.0",
            "versionEndExcluding": "16.0.4275.2"
          }
        ]
      }
    ]
  }
]

Contributing organizations · 2

microsoft

Assigning organization

2026-10-31

CISA-ADP

Additional data publisher

2026-09-08

Timeline

All times UTC

8 Sept 2026, 17:14
Advisory published
Publication date supplied by the source.
31 Oct 2026, 16:13
Source updated
Latest modification date supplied by the source.
31 Oct 2026, 16:21
Last imported by cve.new
Latest catalog import, not the date we first saw this advisory.

What changed

Follow changes

No substantive changes have been recorded here yet. History starts when cve.new observes a change after tracking is enabled; earlier edits are not reconstructed.

Large field values are marked as truncated previews. Original source snapshots remain retained.

Reading the signals

Severity · CVSS: Technical impact and attack conditions. The headline is the highest imported catalog score; sources may disagree.
Observed exploitation · KEV: An absent or unavailable KEV listing does not establish that exploitation has not occurred.
Predicted exploitation · EPSS: 1.00% estimated probability in the next 30 days. 2026-10-31 · FIRST EPSS.

CISA-ADP · SSVC

CISA Coordinator · 2026-09-08

Exploitation: none
Automatable: no
Technical Impact: partial

SSVC describes the publisher’s decision context. Your organization’s exposure and priorities may differ.

Record identifiers

Aliases: None recorded

Source evidence

Request a correction or dispute

Start with the assigning organization for this record. Include the CVE ID, the disputed information, and supporting evidence. A dispute does not itself reject a record.

Find the responsible CNA →Official dispute and escalation process ↗

CVE CVE-2026-66816