CVE-2026-40209

MEDIUMPre-NVD 5.35.3—
EchelonGraph scoreMEDIUM confidence

Score 5.3 from GitHub Security Advisory published 2026-06-25. a secondary CVSS source baseline 5.3; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
5.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.7%CVSS: 5.3Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

An attacker might be able to cause outgoing TCP connections to backend to be stuck until a timeout occurs instead of being released immediately, by sending IXFR queries. This could be used to cause a denial of service if there is a limit to the number of concurrent connections to this backend, or if the process runs out of file descriptors.

CVSS v3
5.3
EG Score
5.3MEDIUMmedium confidence
EG Risk
28
EG Risk 28/100

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
Severity53% × 45%
Exploitation0% × 40%
Automatability30% × 15%
EPSS PROB
0.7%
EPSS %ILE
51st
KEV
Not listed

Published

June 25, 2026

Last Modified

June 25, 2026

Advisory Details (1)

Auto-updated Jun 25, 2026
Patch available.
generic

PowerDNS Security Advisory 2026-09 for DNSdist: Multiple issues - dnsdist documentation

https://www.dnsdist.org/security-advisories/powerdns-advisory-for-dnsdist-2026-09.html

Vendor Advisories for CVE-2026-40209(1)

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

Affected Packages

(4 across 4 ecosystems)
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
dnsdist1.5.1-3 ... 2.1.0-2 (44 versions)
  • every version on: no fix on record
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
dnsdist1.7.3-2 ... 2.1.2-1 (37 versions)
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
dnsdist1.9.10-1, 1.9.10-1+deb13u1, 1.9.14-0+deb13u1
  • every version up to 1.9.15-0+deb13u1: fixed in 1.9.15-0+deb13u1
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
dnsdist1.9.10-1 ... 2.0.6-1 (18 versions)
  • every version up to 2.1.0-1: fixed in 2.1.0-1
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 7× in last 7d / 32× 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 183 total refreshes for this CVE.

  1. 2026-10-10 20:00 UTCEPSS rescore
  2. 2026-10-09 20:07 UTCEPSS rescore
  3. 2026-10-08 17:12 UTCEPSS rescore
  4. 2026-10-07 23:48 UTCEPSS rescore
  5. 2026-10-06 15:17 UTCEPSS rescore
  6. 2026-10-05 17:43 UTCEPSS rescore
  7. 2026-10-04 23:22 UTCEPSS rescore
  8. 2026-10-03 14:25 UTCEPSS rescore
  9. 2026-10-01 19:50 UTCEPSS rescore
  10. 2026-09-30 15:03 UTCEPSS rescore
  11. 2026-09-27 13:48 UTCEPSS rescore
  12. 2026-09-26 15:58 UTCEPSS rescore
  13. 2026-09-26 00:26 UTCEPSS rescore
  14. 2026-09-23 08:50 UTCEG score recompute
  15. 2026-09-23 08:50 UTCGHSA enrichment
  16. 2026-09-20 20:15 UTCEPSS rescore
  17. 2026-09-18 19:28 UTCEPSS rescore
  18. 2026-09-18 19:28 UTCEPSS rescore
  19. 2026-09-18 07:27 UTCEG score recompute
  20. 2026-09-18 07:27 UTCGHSA enrichment
  21. 2026-09-17 19:30 UTCEPSS rescore
  22. 2026-09-16 14:08 UTCEPSS rescore
  23. 2026-09-16 05:15 UTCEPSS rescore
  24. 2026-09-15 03:11 UTCEPSS rescore
  25. 2026-09-14 01:21 UTCEG score recompute
Show 75 more
  1. 2026-09-14 01:21 UTCGHSA enrichment
  2. 2026-09-13 16:47 UTCEPSS rescore
  3. 2026-09-12 15:50 UTCEG score recompute
  4. 2026-09-12 15:50 UTCGHSA enrichment
  5. 2026-09-12 15:01 UTCEPSS rescore
  6. 2026-09-11 14:53 UTCEPSS rescore
  7. 2026-09-11 09:37 UTCEPSS rescore
  8. 2026-09-10 09:34 UTCEPSS rescore
  9. 2026-09-08 22:00 UTCEPSS rescore
  10. 2026-09-07 16:01 UTCEPSS rescore
  11. 2026-09-06 13:47 UTCEPSS rescore
  12. 2026-09-04 05:06 UTCEPSS rescore
  13. 2026-09-02 14:12 UTCEPSS rescore
  14. 2026-09-01 13:53 UTCEPSS rescore
  15. 2026-09-01 04:39 UTCEPSS rescore
  16. 2026-08-30 19:35 UTCEG score recompute
  17. 2026-08-30 19:35 UTCGHSA enrichment
  18. 2026-08-30 19:17 UTCEPSS rescore
  19. 2026-08-30 01:22 UTCEPSS rescore
  20. 2026-08-28 21:41 UTCEPSS rescore
  21. 2026-08-27 23:56 UTCEG score recompute
  22. 2026-08-27 23:56 UTCGHSA enrichment
  23. 2026-08-27 14:25 UTCEPSS rescore
  24. 2026-08-26 14:46 UTCEPSS rescore
  25. 2026-08-25 13:49 UTCEPSS rescore
  26. 2026-08-24 13:11 UTCEG score recompute
  27. 2026-08-24 13:11 UTCGHSA enrichment
  28. 2026-08-23 11:15 UTCEG score recompute
  29. 2026-08-23 11:15 UTCGHSA enrichment
  30. 2026-08-23 00:19 UTCEPSS rescore
  31. 2026-08-22 10:38 UTCEG score recompute
  32. 2026-08-22 10:38 UTCGHSA enrichment
  33. 2026-08-21 23:49 UTCEPSS rescore
  34. 2026-08-21 07:42 UTCEG score recompute
  35. 2026-08-21 07:42 UTCGHSA enrichment
  36. 2026-08-20 22:55 UTCEPSS rescore
  37. 2026-08-20 07:05 UTCEG score recompute
  38. 2026-08-20 07:05 UTCGHSA enrichment
  39. 2026-08-19 17:03 UTCEPSS rescore
  40. 2026-08-19 01:29 UTCEG score recompute
  41. 2026-08-19 01:29 UTCGHSA enrichment
  42. 2026-08-18 13:48 UTCEPSS rescore
  43. 2026-08-17 13:47 UTCEPSS rescore
  44. 2026-08-17 00:05 UTCEG score recompute
  45. 2026-08-17 00:05 UTCGHSA enrichment
  46. 2026-08-16 14:56 UTCEPSS rescore
  47. 2026-08-16 02:14 UTCEPSS rescore
  48. 2026-08-15 23:27 UTCEG score recompute
  49. 2026-08-15 23:27 UTCGHSA enrichment
  50. 2026-08-15 01:30 UTCEPSS rescore
  51. 2026-08-14 22:49 UTCGHSA enrichment
  52. 2026-08-13 22:11 UTCEG score recompute
  53. 2026-08-13 22:11 UTCGHSA enrichment
  54. 2026-08-13 22:00 UTCEPSS rescore
  55. 2026-08-12 21:34 UTCEG score recompute
  56. 2026-08-12 21:34 UTCGHSA enrichment
  57. 2026-08-12 13:51 UTCEPSS rescore
  58. 2026-08-11 20:57 UTCEG score recompute
  59. 2026-08-11 20:56 UTCGHSA enrichment
  60. 2026-08-11 13:43 UTCEPSS rescore
  61. 2026-08-11 00:00 UTCEPSS rescore
  62. 2026-08-10 20:19 UTCGHSA enrichment
  63. 2026-08-09 19:41 UTCEG score recompute
  64. 2026-08-09 19:41 UTCGHSA enrichment
  65. 2026-08-09 13:46 UTCEPSS rescore
  66. 2026-08-08 19:04 UTCEG score recompute
  67. 2026-08-08 19:04 UTCGHSA enrichment
  68. 2026-08-08 16:37 UTCEPSS rescore
  69. 2026-08-07 18:26 UTCEG score recompute
  70. 2026-08-07 18:26 UTCGHSA enrichment
  71. 2026-08-06 17:48 UTCEG score recompute
  72. 2026-08-06 17:48 UTCGHSA enrichment
  73. 2026-08-06 13:46 UTCEPSS rescore
  74. 2026-08-05 19:17 UTCEPSS rescore
  75. 2026-08-05 17:10 UTCEG score recompute

Related CVEs(same product + same CWE)

Frequently asked(5)

What is CVE-2026-40209?
CVE-2026-40209 is a medium vulnerability published on June 25, 2026. An attacker might be able to cause outgoing TCP connections to backend to be stuck until a timeout occurs instead of being released immediately, by sending IXFR queries. This could be used to cause a denial of service if there is a limit to the number of concurrent connections to this backend, or…
When was CVE-2026-40209 disclosed?
CVE-2026-40209 was first published on June 25, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-40209 actively exploited?
CVE-2026-40209 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.7% probability of exploitation in the next 30 days (51st percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-40209?
CVE-2026-40209 has a CVSS base score of 5.3 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-40209?
A fix for CVE-2026-40209 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-40209 are linked in the Vendor Advisories panel on this page.

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