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Fencer Vulns
medium 5.9

CVE-2026-48706 json

Envoy Heap Buffer Overflow in TcpStatsdSink

published 2026-06-26 4 mo ago modified 2026-10-25 14 d ago also BIT-envoy-2026-48706 , EUVD-2026-39825 , GHSA-7q3f-gwg7-j8g4

cvss
5.9
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 49%
public exploits
0
none known

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, 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.

Patch / fix

  • bitnami envoy 1.35.13, 1.36.9, 1.37.5, 1.38.3
  • envoyproxy envoy 1.35.13, 1.36.9, 1.37.5, 1.38.3
  • istioctl openSUSE Tumbleweed 1.30.2-1.1

opensuse advisories openSUSE-SU-2026:11141-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-48706 updated cvss 5.9

envoy: Envoy Heap Buffer Overflow in TcpStatsdSink

  • Red Hat OpenShift Service Mesh 2 openshift-service-mesh/proxyv2-rhel9
    affected: workaround, no fix planned “Will not fix”
  • Red Hat OpenShift Service Mesh 3.1 openshift-service-mesh/istio-proxyv2-rhel9 1784953556
    fixed: vendor fix RHSA-2026:49729
  • Red Hat OpenShift Service Mesh 3.2 openshift-service-mesh/istio-proxyv2-rhel9 1784953743
    fixed: vendor fix RHSA-2026:49744
  • Red Hat OpenShift Service Mesh 3.3 openshift-service-mesh/istio-proxyv2-rhel9 1784908639
    fixed: vendor fix RHSA-2026:49765
  • Red Hat OpenShift Service Mesh 3.1 openshift-service-mesh/istio-cni-rhel9 1784885281, openshift-service-mesh/istio-pilot-rhel9 1784885133, openshift-service-mesh/istio-rhel9-operator 1784918113, openshift-service-mesh/istio-must-gather-rhel9 1784797072, openshift-service-mesh/istio-sail-operator-bundle 1785036397, openshift-service-mesh-tech-preview/istio-ztunnel-rhel9 1784870048 Red Hat OpenShift Service Mesh 3.2 openshift-service-mesh/istio-cni-rhel9 1784921753, openshift-service-mesh/istio-pilot-rhel9 1784921772, openshift-service-mesh/istio-ztunnel-rhel9 1784922382, openshift-service-mesh/istio-rhel9-operator 1784918117, openshift-service-mesh/istio-must-gather-rhel9 1784839815, openshift-service-mesh/istio-sail-operator-bundle 1785036373 Red Hat OpenShift Service Mesh 3.3 openshift-service-mesh/istio-cni-rhel9 1784885810, openshift-service-mesh/istio-pilot-rhel9 1784885681, openshift-service-mesh/istio-ztunnel-rhel9 1784886337, openshift-service-mesh/istio-rhel9-operator 1785316150, openshift-service-mesh/istio-must-gather-rhel9 1784885505, openshift-service-mesh/istio-sail-operator-bundle 1785322241
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
4 mo ago

Exploit prediction

0.61% chance of exploitation in the next 30 days, higher than 49% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
OSV 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
bitnami envoy
>=1.34.0, <1.35.13
>=1.36.0, <1.36.9
>=1.37.0, <1.37.5
>=1.38.0, <1.38.3
1.35.13
1.36.9
1.37.5
1.38.3

Affected products

  • envoyproxy envoy

Classification

Weakness
  • CWE-120 Buffer Copy without Checking Size of Input

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.