CVE-2023-4236

HIGHPre-NVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2023-09-20. a secondary CVSS source baseline 7.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
7.5
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 2%CVSS: 7.5Exploit: NoneExposed: 0

A fix is available — apply it.

A flaw in the networking code handling DNS-over-TLS queries may cause named to terminate unexpectedly due to an assertion failure. This happens when internal data structures are incorrectly reused under significant DNS-over-TLS query load. This issue affects BIND 9 versions 9.18.0 through 9.18.18 and 9.18.11-S1 through 9.18.18-S1.

CVSS v3
7.5
EG Score
7.5(medium)
EG Risk
39(Track)
EG Risk 39/100SSVC: 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
Severity75% × 45%
Exploitation2% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS
80.2%
KEV
Not listed

Published

September 20, 2023

Last Modified

June 17, 2026

References (14)

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntudnsutils (1:9.16.1-0ubuntu2.16) @ focal2026-05-24ubuntu

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Weakness Classification(1)

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

All Vendor Advisories

(1)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 12× in last 7d / 49× 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.

Showing the most recent 100 of 103 total refreshes for this CVE.

  1. 2026-07-23 14:16 UTCEPSS rescore
  2. 2026-07-23 02:26 UTCEG score recompute
  3. 2026-07-22 23:13 UTCEG score recompute
  4. 2026-07-22 14:06 UTCEPSS rescore
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  16. 2026-07-15 09:19 UTCOSV refresh
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  1. 2026-07-08 15:13 UTCEPSS rescore
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  17. 2026-06-27 09:34 UTCOSV refresh
  18. 2026-06-27 03:07 UTCEPSS rescore
  19. 2026-06-25 13:48 UTCEPSS rescore
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  21. 2026-06-24 14:04 UTCEPSS rescore
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  23. 2026-06-23 21:31 UTCEPSS rescore
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  25. 2026-06-21 14:55 UTCEPSS rescore
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  27. 2026-06-21 01:58 UTCEPSS rescore
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  29. 2026-06-19 19:24 UTCEPSS rescore
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  31. 2026-06-18 17:51 UTCEPSS rescore
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  37. 2026-06-13 22:59 UTCEPSS rescore
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  39. 2026-06-12 23:11 UTCEPSS rescore
  40. 2026-06-12 23:10 UTCEPSS rescore
  41. 2026-06-11 13:59 UTCEPSS rescore
  42. 2026-06-10 22:17 UTCEPSS rescore
  43. 2026-06-10 13:21 UTCEPSS rescore
  44. 2026-06-09 20:17 UTCOSV refresh
  45. 2026-06-08 14:16 UTCEPSS rescore
  46. 2026-06-08 14:16 UTCEPSS rescore
  47. 2026-06-07 15:24 UTCEPSS rescore
  48. 2026-06-07 15:23 UTCEPSS rescore
  49. 2026-06-06 13:46 UTCEPSS rescore
  50. 2026-06-06 13:46 UTCEPSS rescore
  51. 2026-06-05 22:46 UTCEPSS rescore
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  67. 2026-05-29 13:43 UTCEPSS rescore
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Frequently asked(5)

What is CVE-2023-4236?
CVE-2023-4236 is a high vulnerability published on September 20, 2023. A flaw in the networking code handling DNS-over-TLS queries may cause named to terminate unexpectedly due to an assertion failure. This happens when internal data structures are incorrectly reused under significant DNS-over-TLS query load. This issue affects BIND 9 versions 9.18.0 through 9.18.18…
When was CVE-2023-4236 disclosed?
CVE-2023-4236 was first published in the National Vulnerability Database on September 20, 2023, with the most recent update on June 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2023-4236 actively exploited?
CVE-2023-4236 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 80.2% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2023-4236?
CVE-2023-4236 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2023-4236?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2023-4236, 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.

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