7.5

CVE-2026-18916: nlnet labs nsd Integer Underflow (Wrap or Wraparound)

CVSS: 7.5v3.1HighAnalyzed
AliasesUBUNTU-CVE-2026-18916DEBIAN-CVE-2026-18916
Published 26-08-2026Last modified 26-08-2026
Open JSON

Vulnerability summary

CVE-2026-18916 is a high (CVSS 7.5) Integer Underflow (Wrap or Wraparound) vulnerability in nlnet labs nsd. EPSS estimates a 0.28% chance of exploitation in the next 30 days, higher than 19.2% of scored vulnerabilities.

Overall risk
30/100
0100
Medium · default modelHow is this calculated?
CVSS score
7.5/10
010
High · v3.1 (NVD)
EPSS score
0.28%
0%100%
Low · -0.08 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 26-08-2026
    PublishedVulnerability first disclosed.
  2. 26-08-2026
    Last modifiedVulnerability information updated.

Description

Any remote client can crash a NSD serve child, by throttling the TCP receive window after a TCP query. By continuously crashing the serve childs, the remote client can denial all TCP service to this NSD instance.

CVSS metrics

6 scores · 4 sources · 2 versions

EPSS trend

Probability

0.28%

Chance of exploitation in the next 30 days

Percentile

19%

Versus all other CVEs

30-day change

-0.08 pp

From 0.36% on 19-09-2026

19-09-202619-10-2026
EPSS score
0.28%

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

Debian1 product
  • nsdAll versions (No fix recorded) | < 4.15.1-1
Nlnet labs1 product
  • nsd≥ 3.2.11, < 4.15.1
Nlnetlabs1 product
  • nsd≥ 3.2.11, < 4.15.1
Ubuntu1 product
  • nsdAll versions (No fix recorded)

4 vendors · 4 products

References

4 links