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TI-2026-34795 Aliases CVE-2026-47207

Envoy crashes if multiple unexpected ext_proc responses are packed into one gRPC message

Priority MEDIUM 62CWE-416Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-416 and the CVSS impact.

Summary

Envoy is an open source edge and service proxy designed for cloud-native applications. From 1.34.0 until 1.35.13, 1.36.9, 1.37.5, and 1.38.3, Envoy crashes if an ext_proc server sends a single gRPC message containing multiple, specially crafted ProcessingResponse messages. This can occur when the first response in the batch causes the gRPC stream object to be destroyed, leading to a use-after-free error when Envoy attempts to process subsequent responses in the same gRPC message. This vulnerability is fixed in 1.35.13, 1.36.9, 1.37.5, and 1.38.3.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00444 38th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Fixed envoy (envoyproxy): 1.38.3, 1.37.5, 1.36.9 +1

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
envoyproxyenvoy1.38.0 to before 1.38.3; 1.37.0 to before 1.37.5; 1.36.0 to before 1.36.9; 1.34.0 to before 1.35.131.38.3, 1.37.5, 1.36.9, 1.35.13Patch availableCNA
  • envoy Vendorenvoyproxy Affected 1.38.0 to before 1.38.3; 1.37.0 to before 1.37.5; 1.36.0 to before 1.36.9; 1.34.0 to before 1.35.13 Fixed in 1.38.3, 1.37.5, 1.36.9, 1.35.13 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*1.34.0 to before 1.35.13; 1.36.0 to before 1.36.9; 1.37.0 to before 1.37.5; 1.38.0 to before 1.38.3Vulnerableenvoyproxy
  • cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:* Versions 1.34.0 to before 1.35.13; 1.36.0 to before 1.36.9; 1.37.0 to before 1.37.5; 1.38.0 to before 1.38.3 Vulnerable ·envoyproxy

Remediation

  • Fix · CNA envoy (envoyproxy) Fixed in 1.38.3, 1.37.5, 1.36.9, 1.35.13

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-47207

References

Exploit 1

  • TI-2026-79288 Out-of-bounds write in Google Brotli decoder KEVCVSS 4.0CRITICAL 9.2
  • TI-2023-23979 The HTTP/2 protocol allows a denial of service (server resource consumption) because… KEVCVSS 3.1HIGH 7.5
  • TI-2024-20001 HTTP/2: CPU exhaustion due to CONTINUATION frame flood CVSS 3.1HIGH 7.5
  • TI-2024-18524 HTTP/2: memory exhaustion due to CONTINUATION frame flood CVSS 3.1HIGH 7.5
  • TI-2023-12215 Envoy client may fake the header `x-envoy-original-path` CVSS 3.1CRITICAL 9.1
  • TI-2023-18002 Envoy vulnerable to OAuth2 credentials exploit with permanent validity CVSS 3.1CRITICAL 9.8
See all 126 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences