CVE-2026-56444

MEDIUMPre-NVD 5.95.9—
EchelonGraph scoreHIGH confidence

Score 5.9 from GitHub Security Advisory published 2026-07-22. a secondary CVSS source baseline 5.9; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 5 sources updated this week
5.9EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.9Exploit: None knownExposed: 0

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

In NLnet Labs Unbound 1.20.0 up to and including 1.25.1, when Unbound is configured with 'serve-expired: yes' and 'serve-expired-client-timeout > discard-timeout > 0' (contrary to the suggested values), the discard-timeout branch during the serve expired logic drops an aged client reply without performing the correct accounting for the number of reply addresses for the query. Other identical branches outside of serve expired perform the correct decrement. Since the counter is never decremented in such scenario, it can reach the maximum limit and new clients for duplicate in-flight queries are silently dropped resulting in degradation of resolution service. A malicious actor can exploit the vulnerability by querying the resolver for a client-controlled slow-on-demand authoritative zone that can drive the counter past the threshold. Shipped defaults for 'serve-expired-client-timeout: 1800' and 'discard-timeout: 1900' make the branch unreachable.

CVSS v3
5.9
EG Score
5.9(high)
EG Risk
42(Track)
EG Risk 42/100SSVC: 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
Severity59% × 45%
Exploitation0% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
15%
KEV
Not listed

Published

July 22, 2026

Last Modified

July 24, 2026

Advisory Details (1)

Auto-updated Jul 22, 2026
No patch confirmed yet.
generic
https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-56444.txt

Vendor Advisories for CVE-2026-56444(2)

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 16× in last 7d / 16× 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 03:31 UTCEG score recompute
  2. 2026-07-27 03:31 UTCVendor advisory
  3. 2026-07-27 03:30 UTCGHSA enrichment
  4. 2026-07-26 14:54 UTCEPSS rescore
  5. 2026-07-26 03:28 UTCEG score recompute
  6. 2026-07-26 03:28 UTCVendor advisory
  7. 2026-07-26 03:27 UTCGHSA enrichment
  8. 2026-07-25 14:18 UTCEPSS rescore
  9. 2026-07-24 14:18 UTCEPSS rescore
  10. 2026-07-23 14:18 UTCEPSS rescore
  11. 2026-07-23 03:20 UTCEG score recompute
  12. 2026-07-22 22:01 UTCEG score recompute
  13. 2026-07-22 22:00 UTCGHSA enrichment
  14. 2026-07-22 14:54 UTCEG score recompute
  15. 2026-07-22 13:17 UTCEG score recompute
  16. 2026-07-22 13:17 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-56444?
CVE-2026-56444 is a medium vulnerability published on July 22, 2026. In NLnet Labs Unbound 1.20.0 up to and including 1.25.1, when Unbound is configured with 'serve-expired: yes' and 'serve-expired-client-timeout > discard-timeout > 0' (contrary to the suggested values), the discard-timeout branch during the serve expired logic drops an aged client reply without…
When was CVE-2026-56444 disclosed?
CVE-2026-56444 was first published in the National Vulnerability Database on July 22, 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-2026-56444 actively exploited?
CVE-2026-56444 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 85.1% of all scored CVEs.
What is the CVSS score of CVE-2026-56444?
CVE-2026-56444 has a CVSS v3 base score of 5.9 (NVD).
How do I remediate CVE-2026-56444?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-56444, 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

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