CVE-2026-44433

HIGHNVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.5 under NVD CVSS v3. EPSS exploit probability: 0.3%, top 80% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
7.5EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.5Exploit: None knownExposed: 0

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

Quicly is an IETF QUIC protocol implementation intended primarily for use within the H2O HTTP server. Prior to commit 8b178e6, an adversarial peer could send a STREAM frame carrying just one byte at the largest offset being permitted to obtain additional flow control credit, which under certain circumstances could lead to a Denial of Service. Assuming the application prepares a receive buffer for storing all data that arrive out-of-order, up to the largest offset being received, this behavior could lead to the application allocating large amount of memory with the peer sending only a handful of packets, resulting in memory exhaustion. In addition to the receive buffer allocation strategy, the severity of this vulnerability depends on how the application controls the stream concurrency. In case of the H2O HTTP server, under its default setting, this bug increases the maximum amount of memory allocated per connection by about 4 times. This issue has been fixed by commit 8b178e6.

CVSS v3
7.5
EG Score
7.5(medium)
EG Risk
49(Track)
EG Risk 49/100SSVC: 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%
Exploitation0% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
20%
KEV
Not listed

Published

July 16, 2026

Last Modified

August 6, 2026

Advisory Details (2)

Auto-updated Jul 17, 2026
Patch available. Sources: github, github_commit.
github Patch Available

memory exhaustion · Advisory · h2o/quicly · GitHub

https://github.com/h2o/quicly/security/advisories/GHSA-f7qr-4p37-9gx9
github_commit

commit 8b178e692c51 (h2o/quicly)

Fix landed in h2o/quicly commit 8b178e692c51 — awaiting tagged release

https://github.com/h2o/quicly/commit/8b178e692c51a3b1031612ef89f03a53aac63c15

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 8× in last 7d / 41× 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.

  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. 2026-09-08 00:24 UTCEG score recompute
  6. 2026-09-07 16:01 UTCEPSS rescore
  7. 2026-09-06 13:47 UTCEPSS rescore
  8. 2026-09-05 20:33 UTCEG score recompute
  9. 2026-09-04 05:06 UTCEPSS rescore
  10. 2026-09-02 14:12 UTCEPSS rescore
  11. 2026-09-01 13:54 UTCEPSS rescore
  12. 2026-08-31 03:02 UTCEG score recompute
  13. 2026-08-30 19:17 UTCEPSS rescore
  14. 2026-08-30 03:28 UTCEG score recompute
  15. 2026-08-30 01:22 UTCEPSS rescore
  16. 2026-08-28 21:41 UTCEPSS rescore
  17. 2026-08-27 23:53 UTCEG score recompute
  18. 2026-08-27 14:25 UTCEPSS rescore
  19. 2026-08-26 23:18 UTCEG score recompute
  20. 2026-08-26 14:46 UTCEPSS rescore
  21. 2026-08-26 00:56 UTCEG score recompute
  22. 2026-08-25 13:49 UTCEPSS rescore
  23. 2026-08-24 15:18 UTCEG score recompute
  24. 2026-08-22 07:37 UTCEG score recompute
  25. 2026-08-21 23:49 UTCEPSS rescore
Show 65 more
  1. 2026-08-21 09:23 UTCEG score recompute
  2. 2026-08-20 22:55 UTCEPSS rescore
  3. 2026-08-19 23:50 UTCEG score recompute
  4. 2026-08-19 17:04 UTCEPSS rescore
  5. 2026-08-18 20:43 UTCEG score recompute
  6. 2026-08-18 13:48 UTCEPSS rescore
  7. 2026-08-17 21:18 UTCEG score recompute
  8. 2026-08-17 13:47 UTCEPSS rescore
  9. 2026-08-16 19:15 UTCEG score recompute
  10. 2026-08-16 14:56 UTCEPSS rescore
  11. 2026-08-16 07:48 UTCEG score recompute
  12. 2026-08-16 02:14 UTCEPSS rescore
  13. 2026-08-15 09:34 UTCEG score recompute
  14. 2026-08-15 01:30 UTCEPSS rescore
  15. 2026-08-14 00:13 UTCEG score recompute
  16. 2026-08-13 22:00 UTCEPSS rescore
  17. 2026-08-12 14:51 UTCEG score recompute
  18. 2026-08-12 13:51 UTCEPSS rescore
  19. 2026-08-11 16:37 UTCEG score recompute
  20. 2026-08-11 13:43 UTCEPSS rescore
  21. 2026-08-11 05:29 UTCEG score recompute
  22. 2026-08-11 00:00 UTCEPSS rescore
  23. 2026-08-09 20:08 UTCEG score recompute
  24. 2026-08-09 13:46 UTCEPSS rescore
  25. 2026-08-08 21:54 UTCEG score recompute
  26. 2026-08-08 16:37 UTCEPSS rescore
  27. 2026-08-07 23:38 UTCEG score recompute
  28. 2026-08-06 14:17 UTCEG score recompute▲ 2.20
  29. 2026-08-06 14:16 UTCNVD updateCVSS v3 → 7.5 · severity → HIGH
  30. 2026-08-06 13:46 UTCEPSS rescore
  31. 2026-08-06 02:04 UTCEG score recompute
  32. 2026-08-05 19:17 UTCEPSS rescore
  33. 2026-08-05 00:39 UTCEG score recompute
  34. 2026-08-04 15:10 UTCEPSS rescore
  35. 2026-08-04 10:38 UTCEPSS rescore
  36. 2026-08-03 23:02 UTCEG score recompute
  37. 2026-08-03 10:36 UTCEPSS rescore
  38. 2026-08-02 21:37 UTCEG score recompute
  39. 2026-08-02 02:27 UTCEPSS rescore
  40. 2026-08-01 20:11 UTCEG score recompute
  41. 2026-08-01 04:16 UTCEPSS rescore
  42. 2026-07-30 17:18 UTCEG score recompute
  43. 2026-07-30 16:28 UTCEPSS rescore
  44. 2026-07-30 01:30 UTCEPSS rescore
  45. 2026-07-29 15:53 UTCEG score recompute
  46. 2026-07-28 15:36 UTCEPSS rescore
  47. 2026-07-28 14:28 UTCEG score recompute
  48. 2026-07-27 14:13 UTCEPSS rescore
  49. 2026-07-27 13:02 UTCEG score recompute
  50. 2026-07-26 14:54 UTCEPSS rescore
  51. 2026-07-26 14:54 UTCEPSS rescore
  52. 2026-07-26 11:23 UTCEG score recompute
  53. 2026-07-25 14:18 UTCEPSS rescore
  54. 2026-07-24 14:17 UTCEPSS rescore
  55. 2026-07-23 14:18 UTCEPSS rescore
  56. 2026-07-23 03:15 UTCEG score recompute
  57. 2026-07-22 14:08 UTCEPSS rescore
  58. 2026-07-21 15:24 UTCEPSS rescore
  59. 2026-07-20 17:08 UTCEPSS rescore
  60. 2026-07-19 14:31 UTCEPSS rescore
  61. 2026-07-19 02:32 UTCEG score recompute
  62. 2026-07-19 02:29 UTCEPSS rescore
  63. 2026-07-18 10:04 UTCEPSS rescore
  64. 2026-07-16 23:43 UTCEG score recompute
  65. 2026-07-16 23:43 UTCNVD updatefirst tracked

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Frequently asked(5)

What is CVE-2026-44433?
CVE-2026-44433 is a high vulnerability published on July 16, 2026. Quicly is an IETF QUIC protocol implementation intended primarily for use within the H2O HTTP server. Prior to commit 8b178e6, an adversarial peer could send a STREAM frame carrying just one byte at the largest offset being permitted to obtain additional flow control credit, which under certain…
When was CVE-2026-44433 disclosed?
CVE-2026-44433 was first published in the National Vulnerability Database on July 16, 2026, with the most recent update on August 6, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-44433 actively exploited?
CVE-2026-44433 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 79.8% of all scored CVEs.
What is the CVSS score of CVE-2026-44433?
CVE-2026-44433 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-44433?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-44433, 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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