Envoy Heap Buffer Overflow in TcpStatsdSink_CVE-2026-48706

5.9 / 10

MEDIUM

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

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.

Basic Information

ID CVE-2026-48706

Source GitHub_M

Published Jun 26, 2026 at 17:38

Affected Product

Vendor envoyproxy

Product envoy

Version >= 1.38.0, < 1.38.3

Affected Versions envoyproxy envoy >= 1.38.0, < 1.38.3
envoyproxy envoy >= 1.37.0, < 1.37.5
envoyproxy envoy >= 1.36.0, < 1.36.9
envoyproxy envoy >= 1.34.0, < 1.35.13

CWE Classification

CWE-120

References

github.com /envoyproxy/envoy/security/advisories/GHSA-7q3f-gwg7-j8g4

{
    "lastseen": "",
    "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\u2014for 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\u2014the 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": "2026-06-26T17:38:23.581Z",
    "modified": "2026-06-26T17:38:23.581Z",
    "type": "cve",
    "title": "Envoy Heap Buffer Overflow in TcpStatsdSink",
    "source": "GitHub_M",
    "references": "https://github.com/envoyproxy/envoy/security/advisories/GHSA-7q3f-gwg7-j8g4",
    "id": "CVE-2026-48706",
    "bulletinFamily": "",
    "cwe": [
        "CWE-120"
    ],
    "cvelist": null,
    "sourceData": "envoyproxy envoy >= 1.38.0, < 1.38.3\nenvoyproxy envoy >= 1.37.0, < 1.37.5\nenvoyproxy envoy >= 1.36.0, < 1.36.9\nenvoyproxy envoy >= 1.34.0, < 1.35.13",
    "sourceHref": "",
    "cvss": {
        "score": 5.9,
        "severity": "MEDIUM",
        "vector": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H",
        "version": "3.1"
    },
    "cvss2": [],
    "cvss3": {
        "version": "",
        "vectorString": "",
        "baseScore": 0,
        "baseSeverity": "",
        "attackVector": "",
        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
            "vectorString": "",
            "baseScore": 0,
            "baseSeverity": "",
            "attackVector": "",
            "attackComplexity": "",
            "privilegesRequired": "",
            "userInteraction": "",
            "scope": "",
            "confidentialityImpact": "",
            "integrityImpact": "",
            "availabilityImpact": ""
        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "envoy",
    "version": ">= 1.38.0, < 1.38.3",
    "vendor": "envoyproxy",
    "ai_description": "",
    "ai_severity": "",
    "ai_vendor": "",
    "ai_product": "",
    "ai_version": "",
    "ai_score": 0
}