CVE-2023-26552
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 · uneditedmstolfp in libntp/mstolfp.c in NTP 4.2.8p15 has an out-of-bounds write when adding a decimal point. An adversary may be able to attack a client ntpq process, but cannot attack ntpd.
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 confidenceThe mstolfp function in libntp/mstolfp.c of NTP 4.2.8p15 contains an out-of-bounds write vulnerability when processing decimal points during string-to-floating-point conversion. This flaw affects the ntpq client utility but does not impact the ntpd daemon, meaning clients running ntpq queries could be exploited by a malicious server or man-in-the-middle attacker.
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= 4.2.8CVSS 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
- High
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- Low
- Integrity
- Low
- Availability
- Low
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L
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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Confirm ntpq client is installedRun 'which ntpq' or 'ntpq --version' to verify the ntpq client utility exists on the systemAffected if ntpq is present and the version is 4.2.8, meaning the vulnerable mstolfp function in libntp/mstolfp.c could be invoked during string-to-floating-point conversion
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Check installed NTP versionRun 'ntpq --version' or check the ntp package version via package manager (dpkg -l ntp, rpm -qi ntp, etc.)Affected if The installed version is exactly 4.2.8, which contains the vulnerable mstolfp function with the out-of-bounds write flaw in decimal point processing
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Verify ntpq connects to remote NTP serversCheck ntpq configuration files (typically /etc/ntp.conf or /etc/ntp/ntp.conf) and review any cron jobs or scripts that run ntpq with remote server queriesAffected if ntpq is configured to query remote NTP servers or is used interactively to connect to untrusted NTP servers, allowing the vulnerable decimal point parsing code to be triggered by malicious server responses
A system is affected if it runs ntpq version 4.2.8 and uses it to query remote NTP servers, as the out-of-bounds write in the mstolfp function triggers during decimal point processing in server response data.
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.
From vendor dataUpgrade to an NTP version containing the patched mstolfp function, or apply the specific bounds-checking fix to the decimal point handling logic in libntp/mstolfp.c.
- Consultation2.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,800.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2023-26552 — 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-2023-26552 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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