CVE-2026-47774

HIGHPre-NVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.8%, top 47% 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, secondary
7.5
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 1%CVSS: 7.5Exploit: NoneExposed: 0

A fix is available — apply it.

Envoy is an open source edge and service proxy designed for cloud-native applications. Prior to versions 1.35.11, 1.36.7, 1.37.3, and 1.38.1, a vulnerability in Envoy's HTTP/2 downstream request processing allows an unauthenticated remote client to trigger excessive memory consumption, potentially resulting in OOM termination of the Envoy process and denial of service. The issue arises from the combination of two behaviors. First, cookie header bytes are not fully accounted for during request header size validation in Envoy. Second, HPACK header block limits in oghttp2/quiche are enforced on encoded bytes without a corresponding limit on total decoded header size. Together, these behaviors allow a malicious client to cause large decoded header allocations while bypassing the intended request header size protections. Versions 1.35.11, 1.36.7, 1.37.3, and 1.38.1 contain a fix. No complete workaround is known short of applying a fix. Possible temporary mitigations include disabling downstream HTTP/2 where operationally feasible; enforcing stricter request header and cookie limits before traffic reaches Envoy; and monitoring Envoy memory usage for abnormal growth under HTTP/2 traffic.

CVSS v3
7.5
EG Score
7.5(medium)
EG Risk
—
EPSS
53.3%
KEV
Not listed

Published

June 17, 2026

Last Modified

July 20, 2026

Advisory Details (2)

Auto-updated Jun 17, 2026
Patch available. Sources: github.
generic

oss-security - Re: HTTP/2 Bomb affects Apache httpd, nginx, envoy, & pingora

http://www.openwall.com/lists/oss-security/2026/06/04/15
github Patch Available

HTTP/2 memory exhaustion via cookie header size bypass and HPACK amplification · Advisory · envoyproxy/envoy · GitHub

https://github.com/envoyproxy/envoy/security/advisories/GHSA-22m2-hvr2-xqc8

Vendor Advisories for CVE-2026-47774(6)

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

Patch Availability(5)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatopenshift-service-mesh/proxyv2-rhel9:17816047242026-06-18redhat
redhatopenshift-service-mesh/istio-proxyv2-rhel9:17810699082026-06-16redhat
redhatopenshift-service-mesh/istio-proxyv2-rhel9:17810701582026-06-16redhat
redhatopenshift-service-mesh/istio-proxyv2-rhel9:17810709672026-06-16redhat
redhatopenshift-service-mesh/istio-proxyv2-rhel9:17810945202026-06-16redhat

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(3)

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

Data Freshness Timeline

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

Frequently asked(5)

What is CVE-2026-47774?
CVE-2026-47774 is a high vulnerability published on June 17, 2026. Envoy is an open source edge and service proxy designed for cloud-native applications. Prior to versions 1.35.11, 1.36.7, 1.37.3, and 1.38.1, a vulnerability in Envoy's HTTP/2 downstream request processing allows an unauthenticated remote client to trigger excessive memory consumption, potentially…
When was CVE-2026-47774 disclosed?
CVE-2026-47774 was first published in the National Vulnerability Database on June 17, 2026, with the most recent update on July 20, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-47774 actively exploited?
CVE-2026-47774 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 53.3% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-47774?
CVE-2026-47774 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-47774?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-47774, 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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