Vulnerability in Envoy (CVE-2026-48706)
Summary
Vulnerability in Envoy (CVE-2026-48706). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 1.35.13 or later.
Original description
The description as published by the source.
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.
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-48706 has been found in Envoy.
Risk of unauthorized operations or information disclosure. CVSS score: 5.9/10.
What to do: upgrade Envoy to 1.35.13 or later.
If unsure, ask your IT team or search "Envoy CVE-2026-48706" on the vendor's site.
CVE-2026-48706 (Envoy) — CWE-120 / CVSS v3 5.9
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Patched: 1.35.13 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-120) exists in Envoy.
Check the vendor advisory for the affected versions of Envoy.
Severity: Medium (CVSS 5.9/10). Risk of unauthorized operations or information disclosure.
Update to 1.35.13.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'Envoy' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'Envoy' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
Envoyを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade Envoy to 1.35.13ステージング環境で 1.35.13 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
-
3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
References
- advisory github.com
- advisory nvd.nist.gov
- advisory github.com