Description
Envoy is a high-performance edge/middle/service proxy. Prior to 1.37.1, 1.36.5, 1.35.8, and 1.34.13, an off-by-one write in Envoy::JsonEscaper::escapeString() can corrupt std::string null-termination, causing undefined behavior and potentially leading to crashes or out-of-bounds reads when the resulting string is later treated as a C-string. This vulnerability is fixed in 1.37.1, 1.36.5, 1.35.8, and 1.34.13.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| envoyproxy | envoy | >= 1.37.0, < 1.37.1, >= 1.36.0, < 1.36.5, >= 1.35.0, < 1.35.9, < 1.34.13 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2023 | ecs-service-connect-agent | v1.34.13.0-1.amzn2023 | ALAS2023-2026-1532 |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| Go | github.com/envoyproxy/envoy | 1.37.0 | — | GHSA-56cj-wgg3-x943 |
| Go | github.com/envoyproxy/envoy | >= 1.36.0, <= 1.36.4 | — | GHSA-56cj-wgg3-x943 |
| Go | github.com/envoyproxy/envoy | >= 1.35.0, <= 1.35.8 | — | GHSA-56cj-wgg3-x943 |
| Go | github.com/envoyproxy/envoy | <= 1.34.12 | — | GHSA-56cj-wgg3-x943 |
Advisories 2
- WID-SEC-2026-0704 Google Cloud Platform Envoy Proxy, Istio und Service Mesh: Mehrere Schwachstellen BSI CERT-Bund (WID) · Apr 1, 2026
- ALAS2023-2026-1532 Important: ecs-service-connect-agent security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Apr 1, 2026