CVE-2023-26551 — mstolfp in libntp/mstolfp

mstolfp in libntp/mstolfp.c in NTP 4.2.8p15 has an out-of-bounds write in the cp<cpdec while loop. An adversary may be able to attack a client ntpq process, but cannot attack ntpd.

01What is this vulnerability?

mstolfp in libntp/mstolfp.c in NTP 4.2.8p15 has an out-of-bounds write in the cp<cpdec while loop. An adversary may be able to attack a client ntpq process, but cannot attack ntpd.

02Affected products

Vendor	Product	Versions
n	a / n/a	n/a

03Active exploitation status

Not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog. EPSS is the best forward-looking signal — see the EPSS row above.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Ask SARA in chat to draft a starting detection for this CVE in your stack of choice.

07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2023-04-11T00:00:00.000Z
• Last modified: 2025-02-11T15:32:41.155Z

09References

• github.com — https://github.com/spwpun/ntp-4.2.8p15-cves/blob/main/CVE-2023-26551
• github.com — https://github.com/spwpun/ntp-4.2.8p15-cves/issues/1#issuecomment-1506667321