CVE-2023-27559
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 · uneditedIBM Db2 for Linux, UNIX and Windows (includes Db2 Connect Server) 10.5, 11.1, and 11.5 is vulnerable to a denial of service as the server may crash when using a specially crafted subquery. IBM X-Force ID: 249196.
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 · moderate confidenceIBM Db2 for Linux, UNIX, and Windows versions 10.5, 11.1, and 11.5 contains a denial of service vulnerability where specially crafted subqueries can cause the database server to crash. This is a high-severity (CVSS 7.5) issue that could disrupt database operations.
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>= 11.1, < 11.1.4>= 11.5, < 11.5.8= 10.5= 11.1.4CVSS 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 checksWork through these to decide whether this CVE applies to you.
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Determine installed Db2 versionRun 'db2level' command from a Db2 instance owner or query SELECT * FROM SYSIBMADM.SYSENVIRONMENTAL_INFO WHERE ENVIRONMENTAL_VARIABLE = 'DB2_VERSION';Affected if The returned version falls within 10.5, 11.1.0-11.1.4, or 11.5.0-11.5.7
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Confirm Db2 edition and fix packRun 'db2pd -version' or query SELECT SERVICE_LEVEL FROM TABLE(SYSPROC.ENV_GET_INST_INFO()) as T;Affected if Service pack or fix pack level is below 11.1.4 for v11.1, below 11.5.8 for v11.5, or is exactly 10.5 with no patches applied
If Db2 version is 10.5, 11.1.0-11.1.4, or 11.5.0-11.5.7, the environment is affected by this vulnerability and specially crafted subqueries could crash the database server.
Generated from the published advisory. Verify against your own configuration.
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 · scoped11.1.411.5.8
Apply IBM's security patches for this vulnerability (IBM X-Force ID 249196). Until patches are applied, limit database access to trusted, authenticated users only and monitor for anomalous query patterns.
Db2 11.1.4+ or 11.5.8+ (depending on your current major version)
- Identify your current Db2 version using 'db2level' command or SELECT FROM SYSCAT.VERSION
- For Db2 11.1.x users: Upgrade to Db2 11.1.4 or later (11.1.4, 11.1.5, 11.1.6, etc.)
- For Db2 11.5.x users: Upgrade to Db2 11.5.8 or later (11.5.8, 11.5.9, 11.5.10, etc.)
- For Db2 10.5 users: IBM indicates 10.5 is affected; contact IBM support for extended support options or plan migration to a supported version (11.1.4+ or 11.5.8+)
- After upgrade, verify the fix by testing subquery operations that previously triggered the issue
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation3.0 h
- Implementation4.0 h
- Testing6.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2023-27559 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2023-27559 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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