CVE-2026-39155

MEDIUMPre-NVD 6.56.5—
EchelonGraph scoreHIGH confidence

Score 6.5 from GitHub Security Advisory published 2026-07-23. CISA-ADP (Vulnrichment) CVSS v3.1 baseline 6.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cisa-adp, epss, ghsa
Trending — 5 sources updated this week
6.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 6.5Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
6.5
EG Score
6.5(high)
EG Risk
29(Track)
EG Risk 29/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity65% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
5%
KEV
Not listed

Published

July 23, 2026

Last Modified

July 24, 2026

Advisory Details (2)

Auto-updated Jul 24, 2026
No patch confirmed yet.
generic

Version 3.5.4 – Knot DNS

https://www.knot-dns.cz/2026-04-02-version-354.html
generic

Version 3.4.10 – Knot DNS

https://www.knot-dns.cz/2026-04-01-version-3410.html

Vendor Advisories for CVE-2026-39155(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 15× in last 7d / 15× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-27 14:13 UTCEPSS rescore
  2. 2026-07-27 03:41 UTCEG score recompute
  3. 2026-07-27 03:41 UTCGHSA enrichment
  4. 2026-07-26 03:21 UTCEG score recompute
  5. 2026-07-26 03:21 UTCGHSA enrichment
  6. 2026-07-25 14:18 UTCEPSS rescore
  7. 2026-07-25 14:18 UTCEPSS rescore
  8. 2026-07-24 19:43 UTCEG score recompute▲ 6.50
  9. 2026-07-24 19:43 UTCGHSA enrichment
  10. 2026-07-24 19:42 UTCMITRE cvelistV5CVSS v3 → 6.5 · severity → MEDIUM
  11. 2026-07-24 14:17 UTCEPSS rescore
  12. 2026-07-24 14:17 UTCEPSS rescore
  13. 2026-07-23 22:11 UTCNVD update
  14. 2026-07-23 20:23 UTCEG score recompute
  15. 2026-07-23 20:21 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-39155?
CVE-2026-39155 is a medium vulnerability published on July 23, 2026. 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…
When was CVE-2026-39155 disclosed?
CVE-2026-39155 was first published in the National Vulnerability Database on July 23, 2026, with the most recent update on July 24, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-39155 actively exploited?
CVE-2026-39155 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 95.4% of all scored CVEs.
What is the CVSS score of CVE-2026-39155?
CVE-2026-39155 has a CVSS v3.1 base score of 6.5 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-39155?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-39155, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2026-39155

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