CVE-2026-40211

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%CVSS: 5.3Exploit: None knownExposed: 0

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

An attacker can send crafted DNS over HTTP/3 queries, triggering an exception that prevents some buffer from being freed right away. The buffer will be freed at the end of the QUIC connection, but on some setups it might be possible to open enough concurrent DoH3 streams to trigger an out-of-memory condition, resulting in a denial of service.

CVSS v3
5.3
EG Score
5.3(medium)
EG Risk
28(Track)
EG Risk 28/100SSVC: 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
Severity53% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
22%
KEV
Not listed

Published

June 25, 2026

Last Modified

June 25, 2026

Advisory Details (1)

Auto-updated Jun 27, 2026
No patch confirmed yet.
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-2026-40211(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 rangeFixed inDependents
dnsdist1.5.1-3 ... 2.1.0-2 (44 versions)——
Debian:12(1)
PackageVulnerable rangeFixed inDependents
dnsdist1.7.3-2 ... 2.1.1-1 (36 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
dnsdist1.9.10-1, 1.9.10-1+deb13u1, 1.9.14-0+deb13u11.9.15-0+deb13u1—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
dnsdist1.9.10-1 ... 2.0.6-1 (18 versions)2.1.0-1—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 6× in last 7d / 52× 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 155 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-40211?
CVE-2026-40211 is a medium vulnerability published on June 25, 2026. An attacker can send crafted DNS over HTTP/3 queries, triggering an exception that prevents some buffer from being freed right away. The buffer will be freed at the end of the QUIC connection, but on some setups it might be possible to open enough concurrent DoH3 streams to trigger an out-of-memory…
When was CVE-2026-40211 disclosed?
CVE-2026-40211 was first published in the National Vulnerability Database 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-2026-40211 actively exploited?
CVE-2026-40211 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 77.9% of all scored CVEs.
What is the CVSS score of CVE-2026-40211?
CVE-2026-40211 has a CVSS v3 base score of 5.3 (NVD).
How do I remediate CVE-2026-40211?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-40211, 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

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-40211

Explore →

Is Your Infrastructure Affected by CVE-2026-40211?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Start Free Scan →Browse All CVEs