CVE-2026-42530

HIGHPre-NVD 8.18.1—
EchelonGraph scoreHIGH confidence

Score 8.1 from GitHub Security Advisory (severity: CRITICAL) published 2026-06-17. a secondary CVSS source baseline 8.1; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this weekElevated
8.1
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 3%CVSS: 8.1Exploit: NoneExposed: 0

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

NGINX Open Source has a vulnerability in the ngx_http_v3_module module. When NGINX Open Source is configured to use the HTTP/3 QUIC module, a remote unauthenticated attacker along with conditions beyond their control can use a specially crafted HTTP/3 session to reopen a QPACK encoder stream. This may cause a Use-after-Free in the NGINX worker process leading to a restart. Additionally, attackers can execute code on systems with Address Space Layout Randomization (ASLR) disabled or when the attacker can bypass ASLR.

Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

CVSS v3
8.1
EG Score
8.1(high)
EPSS
86.7%
KEV
Not listed

Published

June 17, 2026

Last Modified

July 2, 2026

Advisory Details (1)

Auto-updated Jun 18, 2026
No patch confirmed yet.
generic

myF5

https://my.f5.com/manage/s/article/K000161616

Vendor Advisories for CVE-2026-42530(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 36× in last 7d / 101× 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 101 total refreshes for this CVE.

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

Publicly available exploits

(1 reference)

Working exploit code is in the public domain (1 GitHub PoC). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • GitHub PoCv4ltonn/CVE-2026-42530
    First seen Jun 19, 2026

    Scanner PoC for CVE-2026-42530 -- nginx 1.31.0-1.31.1 HTTP/3 QPACK encoder stream Use-After-Free (CVSS 9.2)

    Open source ↗

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-42530?
CVE-2026-42530 is a high vulnerability published on June 17, 2026. NGINX Open Source has a vulnerability in the ngxhttpv3_module module. When NGINX Open Source is configured to use the HTTP/3 QUIC module, a remote unauthenticated attacker along with conditions beyond their control can use a specially crafted HTTP/3 session to reopen a QPACK encoder stream. This…
When was CVE-2026-42530 disclosed?
CVE-2026-42530 was first published in the National Vulnerability Database on June 17, 2026, with the most recent update on July 2, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-42530 actively exploited?
CVE-2026-42530 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 86.7% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-42530?
CVE-2026-42530 has a CVSS v3 base score of 8.1 (NVD).
How do I remediate CVE-2026-42530?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-42530, 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-2026-42530

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