CVE-2026-42530

HIGHPre-NVD 8.18.1—
EchelonGraph scoreMEDIUM 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 — 4 sources updated this weekElevated
8.1EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 4%CVSS: 8.1Exploit: Elevated riskExposed: 0

A fix is available — apply it.

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(medium)
EG Risk
52(Track)
EG Risk 52/100SSVC: 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
Severity81% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
4%
EPSS %ILE
90%
KEV
Not listed

Published

June 17, 2026

Last Modified

July 16, 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(2)

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

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatnginx-main-1.30.2-1.hum12026-05-23redhat

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.

Data Freshness Timeline

(refreshed 9× in last 7d / 45× 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 286 total refreshes for this CVE.

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

Publicly available exploits

(2 references)

Working exploit code is in the public domain (2 GitHub PoCs). 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 ↗
  • GitHub PoC0xBlackash/CVE-2026-42530
    First seen Jun 19, 2026

    CVE-2026-42530

    Open source ↗

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 16, 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 4% probability of exploitation in the next 30 days, which ranks it in the top 10.4% of all scored CVEs.
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

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