What is CVE-2026-39155?

CVE-2026-39155 is a medium-severity vulnerability in N/a, classified under Insufficient Verification of Data Authenticity. CVSS score: 6.5/10. Published 2026-07-23.

How severe is CVE-2026-39155?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Vulnerability in N/a

CVE-2026-39155

Knot DNS before 3.4.10 and 3.5.x before 3.5.4 contains a vulnerability in mod-onlinesign where the next NSEC owner name can be computed incorrectly. This can create an overly broad authenticated denial interval, allowing downstream validating resolvers using aggressive negative caching to synthesize negative answers for legitimate names and causing resolver-side denial of service.

EPSS: 0.002 (4.5th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.

Affected products

N/a — versions n/a

Weakness classification (CWE)

CWE-345 — Insufficient Verification of Data Authenticity

References

Frequently asked questions

What is CVE-2026-39155?: CVE-2026-39155 is a medium-severity vulnerability in N/a, classified under Insufficient Verification of Data Authenticity. CVSS score: 6.5/10. Published 2026-07-23.
How severe is CVE-2026-39155?: Medium severity. CVSS v3 base score is 6.5 out of 10.