CVE-2026-48521
published 2026-09-21CVE-2026-48521: Envoy is an open source edge and service proxy designed for cloud-native applications. Prior to 1.36.10, 1.37.6, 1.38.4, and 1.39.1, Envoy's…
PriorityP433medium5.9CVSS 3.1
AVNACHPRNUINSUCNINAH
EPSS
0.74%
54.1th percentile
Envoy is an open source edge and service proxy designed for cloud-native applications. Prior to 1.36.10, 1.37.6, 1.38.4, and 1.39.1, Envoy's ProdClusterManagerFactory::allocateConnPool dereferences transport_socket_options while selecting an HTTP/3 connection pool without first checking whether the pointer is null. LoadBalancerContext implementations used by synthetic, mirror, health-check, and async-client calls can return no transport-socket options. With auto_config and HTTP/3 enabled, routine traffic reaching one of those contexts can crash an Envoy worker. The relevant scope boundary is that the affected branch requires HTTP/3 in the protocol set and a context that supplies no transport-socket options. This issue is fixed in versions 1.36.10, 1.37.6, 1.38.4, and 1.39.1.
Affected
7 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| envoyproxy | envoy | < 1.36.10 | 1.36.10 |
| envoyproxy | envoy | — | — |
| envoyproxy | envoy | — | — |
| envoyproxy | envoy | — | — |
| envoyproxy | envoy | >= 1.37.0 < 1.37.6 | 1.37.6 |
| envoyproxy | envoy | >= 1.38.0 < 1.38.4 | 1.38.4 |
| envoyproxy | envoy | >= 1.39.0 < 1.39.1 | 1.39.1 |
CVSS provenance
nvdv3.15.9MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
vendor_redhat5.9MEDIUM
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Red Hat
envoy: envoy: HTTP/3 null transport socket options dereference during connection-pool selection
vendor_redhat·2026-08-26·CVSS 5.9
CVE-2026-48521 [MEDIUM] CWE-476 envoy: envoy: HTTP/3 null transport socket options dereference during connection-pool selection
envoy: envoy: HTTP/3 null transport socket options dereference during connection-pool selection
No description is available for this CVE.
Package: openshift-service-mesh/istio-proxyv2-rhel9 (OpenShift Service Mesh 3) - Not affected
VulDB
EnvoyProxy Envoy up to 1.36.9/1.37.5/1.38.3/1.39.0 Connection Pool Selection allocateConnPool null pointer dereference
vuldb·2026-09-21·CVSS 5.9
CVE-2026-48521 [MEDIUM] EnvoyProxy Envoy up to 1.36.9/1.37.5/1.38.3/1.39.0 Connection Pool Selection allocateConnPool null pointer dereference
A vulnerability classified as critical has been found in EnvoyProxy Envoy up to 1.36.9/1.37.5/1.38.3/1.39.0. The impacted element is the function ProdClusterManagerFactory::allocateConnPool of the component Connection Pool Selection. The manipulation leads to null pointer dereference.
This vulnerability is traded as CVE-2026-48521. It is possible to initiate the attack remotely. There is no exploit available.
It is recommended to upgrade the affected component.
No detection rules found.
No public exploits indexed.
https://github.com/envoyproxy/envoy/commit/8ef2da8527fcd17388b046c1add4fb47fb5d0868https://github.com/envoyproxy/envoy/commit/cec4899acf03cf551f28611a5f32385648d95f96https://github.com/envoyproxy/envoy/commit/e7b4839beef7f43594ce8e94c4563c80db04a8a7https://github.com/envoyproxy/envoy/commit/f5436f44103fb14cb8ba42a8db0f54a06c98c45ahttps://github.com/envoyproxy/envoy/releases/tag/v1.36.10https://github.com/envoyproxy/envoy/releases/tag/v1.37.6https://github.com/envoyproxy/envoy/releases/tag/v1.38.4https://github.com/envoyproxy/envoy/releases/tag/v1.39.1https://github.com/envoyproxy/envoy/security/advisories/GHSA-5vff-j9p4-38j3https://github.com/envoyproxy/envoy/security/advisories/GHSA-5vff-j9p4-38j3
2026-09-21
Published