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Database ServerDatabase / datastore · Oracle

CVE-2026-46834

HIGH · 7.5 CVSS v3.1 Published 2026-05-28
Fix available
A fix is available. Upgrade to after 23.26.2 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Vulnerability in the Net Service component of Oracle Database Server. Supported versions that are affected are 23.4.0-23.26.2. Easily exploitable vulnerability allows unauthenticated attacker with network access via TLS to compromise Net Service. Successful attacks of this vulnerability can result in unauthorized ability to cause a hang or frequently repeatable crash (complete DOS) of Net Service. CVSS 3.1 Base Score 7.5 (Availability impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

A vulnerability in Oracle Database Server's Net Service component (versions 23.4.0-23.26.2) allows unauthenticated remote attackers with network access via TLS to cause denial of service. The flaw enables attackers to hang or crash the Net Service, potentially leading to complete disruption of database connectivity services.

MitigationApply the relevant Oracle Critical Patch Update (CPU) for CVE-2026-46834 to the affected Oracle Database Server installations. Restrict network access to the Oracle Net Service listener (TCP port 1521 typically) to trusted sources as an interim compensating control until patching is completed.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Database ServerDatabase / datastore
Affected:>= 23.4.0, <= 23.26.2

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify Oracle Database Server installation
    Check for Oracle Database installation by looking for ORACLE_HOME environment variable, or query the Oracle inventory using 'opatch lsinventory' or check the /etc/oratab file
    Affected if Oracle Database Server is not installed on the system
  2. Determine the Oracle Database version
    Connect to the database as SYSDBA and run: SELECT VERSION FROM V$INSTANCE; OR check the Oracle inventory output from 'opatch lsinventory' which lists installed Oracle components and versions
    Affected if The version falls within the range >= 23.4.0 and <= 23.26.2
  3. Check if Oracle Net Service listener is running
    Run 'lsnrctl status' to check if the Oracle Net Listener is active and listening on network ports
    Affected if The listener is running and accessible over the network
  4. Verify TLS is enabled for Oracle Net Listener
    Check the listener.ora configuration file (typically in $ORACLE_HOME/network/admin/) for TLS or TCPS configuration in the LISTENER definition, or run 'lsnrctl status' and look for TCPS or SSL endpoints
    Affected if TLS/TCPS is configured and enabled for the Oracle Net Listener

The environment is affected if Oracle Database Server version 23.4.0 through 23.26.2 is installed with Oracle Net Service running and accessible via TLS.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to a release after 23.26.2
Interim mitigation

Apply the relevant Oracle Critical Patch Update (CPU) for CVE-2026-46834 to the affected Oracle Database Server installations. Restrict network access to the Oracle Net Service listener (TCP port 1521 typically) to trusted sources as an interim compensating control until patching is completed.

Recommended fix Moderate confidence

Oracle Database 23.27.x or later (or apply April 2026 CPU patch)

  1. Check the Oracle Critical Patch Update (CPU) advisory for April 2026 for CVE-2026-46834 on Oracle Support (support.oracle.com)
  2. Identify the specific patch number and platform-specific patch IDs for Oracle Database Net Service component
  3. Download and apply the relevant patch from Oracle Support using OPatch or Oracle Restart
  4. Alternatively, if available, upgrade to Oracle Database 23.27.x or later which contains the fix
  5. After patching, restart the Oracle Net Service (listener) to apply changes
  6. Verify the patch is installed by checking OPatch lsinventory and testing Net Service functionality
Caveat Review Oracle Database 23.27 release notes for any migration considerations before upgrading; test in non-production environment first

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Database Server Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,860
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-46834 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data