CVE-2026-48521

mediumpriority · track · 0EPSS 0.007 · 54 %ileUS

grimoire priorityP3 · Track

Exploitable?

—

no known exploitation

Likely / severe?

0.74% (54th) EPSS

CVSS 5.9 · medium

Is it mine?

8 products

Check your exposure

Who says so?

2 sources

osv · nvd

EPSS · scored 2026-10-28

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.

cvss

Technical severity, 0–10. One row per scoring source.

5.9

010

base score 0–10 · higher = more severe · hover a vector to decode

v3.15.9mediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:Hsecondary · security-advisories@github.comexploitability 2.2 · impact 3.6

v3.15.4mediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H/E:Usecondary · CVSS-BT (t0sche)

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Exploitation: poc · Automatable: no · Technical Impact: partialcoordinatorcisa_ssvcUS

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-476USprimary

affected products (8)

Products and version ranges known to be affected.

envoyproxy envoy< 1.36.10nvdUScpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*
envoyproxy envoy1.37.0 → 1.37.6nvdUScpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*
envoyproxy envoy1.38.0 → 1.38.4nvdUScpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*
envoyproxy envoy1.39.0 → 1.39.1nvdUScpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*
Bitnami envoy< 1.36.10osvUSpkg:bitnami/envoy
Bitnami envoy1.37.0 → 1.37.6osvUSpkg:bitnami/envoy
Bitnami envoy1.38.0 → 1.38.4osvUSpkg:bitnami/envoy
Bitnami envoy1.39.0 → 1.39.1osvUSpkg:bitnami/envoy

advisories (1)

Vendor and ecosystem advisories describing this.

BIT-envoy-2026-48521Envoy: HTTP/3 connection pool selection null-derefs in ProdClusterManagerFactory::allocateConnPool when transport_socket_options is null2026-09-29vendor · osvUS
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.

also known as (1)

Other names and identifiers for this entity.

GHSA-5vff-j9p4-38j3 osv

sources

Which sources assert this record, and when.

osv nvd NVD CVE.org MITRE

published 2026-09-21modified 2026-10-05

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references (9) nvd

External citations — patches, advisories, analysis.

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