vulntracker.iovulntracker.io
© 2026 vulntracker.io

CVE-2026-48521

Envoy: HTTP/3 connection pool selection null-derefs in ProdClusterManagerFactory::allocateConnPool when transport_socket_options is null

MEDIUM
5.9
CVSS Score
Published: September 21, 2026 at 07:44 PM UTC
Updated: October 5, 2026 at 02:09 PM UTC
1 product affected across 1 vendorEnvoy

Using envoy by envoyproxy?

Get instant alerts when new vulnerabilities affect envoy - before attackers find them.

Real-time alertsTrack your software stackFree plan available
Start FreeSign In
Severity
MEDIUM5.9
Exploit prediction
EPSS 0.7%
SSVC
PoC

Description

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

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Envoy· Envoyproxy
95%
v < 1.36.10v < 1.37.6v < 1.38.4v < 1.39.11.37.0 ≤ v < 1.37.61.38.0 ≤ v < 1.38.41.39.0 ≤ v < 1.39.1
Affected range stops below 1.36.10, so it looks safe — our inference, not a vendor statement
Affected range stops below 1.37.6, so it looks safe — our inference, not a vendor statement
Affected range stops below 1.38.4, so it looks safe — our inference, not a vendor statement
Affected range stops below 1.39.1, so it looks safe — our inference, not a vendor statement

References (9)

x_refsource_CONFIRMExploitVendor Advisory
Source: cverecord
https://github.com/envoyproxy/envoy/security/advisories/GHSA-5vff-j9p4-38j3
x_refsource_MISCPatch
Source: cverecord
https://github.com/envoyproxy/envoy/commit/8ef2da8527fcd17388b046c1add4fb47fb5d0868
x_refsource_MISCPatch
Source: cverecord
https://github.com/envoyproxy/envoy/commit/cec4899acf03cf551f28611a5f32385648d95f96
x_refsource_MISCPatch
Source: cverecord
https://github.com/envoyproxy/envoy/commit/e7b4839beef7f43594ce8e94c4563c80db04a8a7
x_refsource_MISCPatch
Source: cverecord
https://github.com/envoyproxy/envoy/commit/f5436f44103fb14cb8ba42a8db0f54a06c98c45a
x_refsource_MISCRelease Notes
Source: cverecord
https://github.com/envoyproxy/envoy/releases/tag/v1.36.10
x_refsource_MISCRelease Notes
Source: cverecord
https://github.com/envoyproxy/envoy/releases/tag/v1.37.6
x_refsource_MISCRelease Notes
Source: cverecord
https://github.com/envoyproxy/envoy/releases/tag/v1.38.4

SSVC — Action Prioritization

SSVCPoCNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

5.9MEDIUMGitHub_M
Attack Vector
NETWORK
Complexity
HIGH
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-476

Get alerted

Stop reading CVE feeds looking for your own stack

Track the products you run and VulnTracker tells you when a new CVE affects them — with what is known about fixing it, and nothing about the rest.

Create accountSign in
Free plan, no card