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Envoy Proxy CVE-2026-47207

| EUVDEUVD-2026-39826 MEDIUM
Use After Free (CWE-416)
2026-06-26 GitHub_M
6.5
CVSS 3.1 · Vendor: GitHub_M
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Severity by source

Vendor (GitHub_M) PRIMARY
6.5 MEDIUM
AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
vuln.today AI
6.5 MEDIUM

Network vector and low complexity are accurate; PR:L reflects mandatory control of the ext_proc gRPC server; only availability impact applies.

3.1 AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
4.0 AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Primary rating from Vendor (GitHub_M).

CVSS VectorVendor: GitHub_M

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

Lifecycle Timeline

2
Patch available
Jun 26, 2026 - 19:02 EUVD
Analysis Generated
Jun 26, 2026 - 18:36 vuln.today

DescriptionCVE.org

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.

AnalysisAI

Envoy proxy's External Processing (ext_proc) filter crashes with a use-after-free when an ext_proc gRPC server sends a single batched gRPC message containing multiple specially crafted ProcessingResponse objects. Affected versions span 1.34.0 through pre-fix releases across four maintained branches; fixed releases are 1.35.13, 1.36.9, 1.37.5, and 1.38.3. …

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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata

Access
Compromise or control configured ext_proc gRPC server
Delivery
Craft gRPC message batching multiple malformed ProcessingResponse frames
Exploit
Deliver batched message to target Envoy instance
Execution
First response triggers gRPC stream object destruction
Persist
Subsequent response dereferences freed stream pointer
Impact
Envoy process crashes (denial of service)

Vulnerability AssessmentAI

Exploitation The ext_proc (External Processing) filter must be explicitly enabled in the Envoy configuration - it is not active by default and requires deliberate opt-in. … Additional conditions and limiting factors are described in the full assessment.
Risk Assessment The CVSS 6.5 vector (AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H) is well-calibrated for this vulnerability. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in.
Exploit Scenario An attacker who has compromised or controls a configured ext_proc gRPC server crafts a single gRPC protocol message that bundles multiple ProcessingResponse frames, where the first frame is designed to trigger destruction of Envoy's gRPC stream object. When Envoy receives and processes the batched message, the iterator accesses the freed stream pointer for subsequent frames, causing a use-after-free crash and taking the proxy process down. …
Remediation Upgrade Envoy to a patched release on your current branch: 1.35.13, 1.36.9, 1.37.5, or 1.38.3, as documented in the vendor advisory at https://github.com/envoyproxy/envoy/security/advisories/GHSA-68cv-hq5f-g6xv. … Detailed patch versions, workarounds, and compensating controls in full report.

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CVE-2026-47207 vulnerability details – vuln.today

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