4.7

CVE-2026-18321: ntpsec Classic Buffer Overflow

CVSS: 4.7v3.1MediumAwaiting analysis
AliasesMGASA-2026-0430UBUNTU-CVE-2026-18321DEBIAN-CVE-2026-18321
Published 31-07-2026Last modified 31-07-2026
Open JSON

Vulnerability summary

CVE-2026-18321 is a medium (CVSS 4.7) Classic Buffer Overflow vulnerability in ntpsec. EPSS estimates a 0.11% chance of exploitation in the next 30 days, higher than 1.2% of scored vulnerabilities.

Overall risk
19/100
0100
Low · default modelHow is this calculated?
CVSS score
4.7/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.11%
0%100%
Low · +0.03 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 31-07-2026
    PublishedVulnerability first disclosed.
  2. 31-07-2026
    Last modifiedVulnerability information updated.

Description

Buffer overflow in NTPsec's Zyfer refclock allows local attacker to crash ntpd

CVSS metrics

4 scores · 4 sources · 1 version

EPSS trend

Probability

0.11%

Chance of exploitation in the next 30 days

Percentile

1%

Versus all other CVEs

30-day change

+0.03 pp

From 0.08% on 19-09-2026

19-09-202619-10-2026
EPSS score
0.11%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Mageia2 products
  • ntpsec< 1.2.4-3.2.mga10
  • ntpsec< 1.2.2-5.1.mga9
Debian1 product
  • ntpsecAll versions (No fix recorded) | < 1.2.5+dfsg-1
Ntpsec1 product
Opensuse1 product
  • ntpsec&distro=openSUSE Tumbleweed< 1.2.5-1.1
Ubuntu1 product
  • ntpsecAll versions (No fix recorded)

5 vendors · 6 products

References

9 links