Description
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, a vulnerability exists in Envoy's TCP StatsD sink (TcpStatsdSink), where the thread-local flusher buffer can be overflowed by exceptionally long statistic names (e.g., >16KiB). During formatting, TcpStatsdSink reserves a single contiguous memory slice of 16KiB (FLUSH_SLICE_SIZE_BYTES). If formatting a single metric exceeds the remaining capacity, the flusher initiates a buffer rotation but incorrectly continues to allocate another fixed 16KiB slice. If an attacker can trigger a statistic name longer than 16KiB—for example, by sending an HTTP or gRPC request with an extremely long request path (:path) that is recorded by the grpc_stats filter configured with stats_for_all_methods: true—the flusher will attempt to copy the metric name using memcpy operations beyond the allocated heap buffer boundaries. This leads to a heap write overflow, which can cause immediate denial-of-service (process crash) or potential remote code execution (RCE). This vulnerability is fixed in 1.35.13, 1.36.9, 1.37.5, and 1.38.3.
Published: 2026-06-26
Score: 5.9 Medium
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
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Remediation

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History

Fri, 26 Jun 2026 23:00:00 +0000

Type Values Removed Values Added
First Time appeared Envoyproxy
Envoyproxy envoy
Vendors & Products Envoyproxy
Envoyproxy envoy

Fri, 26 Jun 2026 19:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Fri, 26 Jun 2026 18:15:00 +0000

Type Values Removed Values Added
Description 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, a vulnerability exists in Envoy's TCP StatsD sink (TcpStatsdSink), where the thread-local flusher buffer can be overflowed by exceptionally long statistic names (e.g., >16KiB). During formatting, TcpStatsdSink reserves a single contiguous memory slice of 16KiB (FLUSH_SLICE_SIZE_BYTES). If formatting a single metric exceeds the remaining capacity, the flusher initiates a buffer rotation but incorrectly continues to allocate another fixed 16KiB slice. If an attacker can trigger a statistic name longer than 16KiB—for example, by sending an HTTP or gRPC request with an extremely long request path (:path) that is recorded by the grpc_stats filter configured with stats_for_all_methods: true—the flusher will attempt to copy the metric name using memcpy operations beyond the allocated heap buffer boundaries. This leads to a heap write overflow, which can cause immediate denial-of-service (process crash) or potential remote code execution (RCE). This vulnerability is fixed in 1.35.13, 1.36.9, 1.37.5, and 1.38.3.
Title Envoy Heap Buffer Overflow in TcpStatsdSink
Weaknesses CWE-120
References
Metrics cvssV3_1

{'score': 5.9, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H'}

Subscriptions

Envoyproxy Envoy
cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-06-26T19:05:30.344Z

Reserved: 2026-05-22T18:47:27.754Z

Link: CVE-2026-48706

cve-icon Vulnrichment

Updated: 2026-06-26T19:05:18.309Z

cve-icon NVD

No data.

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-06-26T22:45:05Z

Weaknesses