CVE-2026-48521 (GCVE-0-2026-48521)
Vulnerability from cvelistv5 – Published: 2026-09-21 19:44 – Updated: 2026-09-21 20:04
VLAI
EPSS
VEX
Title
Envoy: HTTP/3 connection pool selection null-derefs in ProdClusterManagerFactory::allocateConnPool when transport_socket_options is null
Summary
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.
Severity
5.9 (Medium)
SSVC
Exploitation: poc
Automatable: no
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-09-21 20:02 UTC
CWE
- CWE-476 - NULL Pointer Dereference
Assigner
References
9 references
| URL | Tags |
|---|---|
| https://github.com/envoyproxy/envoy/security/advi… | x_refsource_CONFIRM |
| https://github.com/envoyproxy/envoy/commit/8ef2da… | x_refsource_MISC |
| https://github.com/envoyproxy/envoy/commit/cec489… | x_refsource_MISC |
| https://github.com/envoyproxy/envoy/commit/e7b483… | x_refsource_MISC |
| https://github.com/envoyproxy/envoy/commit/f5436f… | x_refsource_MISC |
| https://github.com/envoyproxy/envoy/releases/tag/… | x_refsource_MISC |
| https://github.com/envoyproxy/envoy/releases/tag/… | x_refsource_MISC |
| https://github.com/envoyproxy/envoy/releases/tag/… | x_refsource_MISC |
| https://github.com/envoyproxy/envoy/releases/tag/… | x_refsource_MISC |
Impacted products
1 product
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| envoyproxy | envoy |
Affected:
< 1.36.10
Affected: >= 1.37.0, < 1.37.6 Affected: >= 1.38.0, < 1.38.4 Affected: >= 1.39.0, < 1.39.1 |
guessed |
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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