Incomplete Internal State Distinction in ntpsec

published 2023-08-07 3 y ago modified 2026-06-22 4 mo ago also EUVD-2023-53905

cvss: 7.5; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.4%; EPSS 0.4% chance of exploitation in 30 days, percentile 39%
public exploits: 0; none known

ntpd will crash if the server is not NTS-enabled (no certificate) and it receives an NTS-enabled client request (mode 3).

Patch / fix

distros 2

debian alpine

ntpsec Debian 12 1.2.2+dfsg1-1+deb12u1
ntpsec Debian 14, Debian 13 1.2.2+dfsg1-2

debian advisories DEBIAN-CVE-2023-4012

ntpsec Alpine 3.24, Alpine 3.23, Alpine 3.22 +4 more 1.2.2a-r0

alpine advisories ALPINE-CVE-2023-4012

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2023-4012 updated 2026-06-28

ntpsec: crash after client request

Red Hat All currently supported Red Hat products
not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation: none
Automatable: yes
Technical impact: partial
Assessed: 2 y ago (2024-08-30)

Exploit prediction

0.45% chance of exploitation in the next 30 days, higher than 39% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD	3.1	7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

NTPsec ntpsec

Classification

Weakness

CWE-372 Incomplete Internal State Distinction

References

gitlab.com /NTPsec/ntpsec/-/issues/794
issue-tracking, vendor-advisory
bugs.debian.org /cgi-bin/bugreport.cgi?bug=1038422
issue-tracking, third-party-advisory

Sources

CVE List CVE-2023-4012
NVD CVE-2023-4012

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary