Vulnerability-Lookup

FKIE_CVE-2026-47774

Vulnerability from fkie_nvd - Published: 2026-06-17 18:18 - Updated: 2026-10-26 11:10

Severity

7.5 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.5 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Summary

Envoy is an open source edge and service proxy designed for cloud-native applications. Prior to versions 1.35.11, 1.36.7, 1.37.3, and 1.38.1, a vulnerability in Envoy's HTTP/2 downstream request processing allows an unauthenticated remote client to trigger excessive memory consumption, potentially resulting in OOM termination of the Envoy process and denial of service. The issue arises from the combination of two behaviors. First, cookie header bytes are not fully accounted for during request header size validation in Envoy. Second, HPACK header block limits in oghttp2/quiche are enforced on encoded bytes without a corresponding limit on total decoded header size. Together, these behaviors allow a malicious client to cause large decoded header allocations while bypassing the intended request header size protections. Versions 1.35.11, 1.36.7, 1.37.3, and 1.38.1 contain a fix. No complete workaround is known short of applying a fix. Possible temporary mitigations include disabling downstream HTTP/2 where operationally feasible; enforcing stricter request header and cookie limits before traffic reaches Envoy; and monitoring Envoy memory usage for abnormal growth under HTTP/2 traffic.

References

URL	Tags
security-advisories@github.com	https://github.com/envoyproxy/envoy/security/advisories/GHSA-22m2-hvr2-xqc8	Mitigation, Vendor Advisory
af854a3a-2127-422b-91ae-364da2661108	http://www.openwall.com/lists/oss-security/2026/06/04/15	Mailing List, Mitigation, Third Party Advisory
0b0ca135-0b70-47e7-9f44-1890c2a1c46c	https://access.redhat.com/errata/RHSA-2026:26210	Third Party Advisory
0b0ca135-0b70-47e7-9f44-1890c2a1c46c	https://access.redhat.com/errata/RHSA-2026:26222	Third Party Advisory
0b0ca135-0b70-47e7-9f44-1890c2a1c46c	https://access.redhat.com/errata/RHSA-2026:26231	Third Party Advisory
0b0ca135-0b70-47e7-9f44-1890c2a1c46c	https://access.redhat.com/errata/RHSA-2026:26247	Third Party Advisory
0b0ca135-0b70-47e7-9f44-1890c2a1c46c	https://access.redhat.com/errata/RHSA-2026:27114	Third Party Advisory
0b0ca135-0b70-47e7-9f44-1890c2a1c46c	https://access.redhat.com/security/cve/CVE-2026-47774	Third Party Advisory
0b0ca135-0b70-47e7-9f44-1890c2a1c46c	https://bugzilla.redhat.com/show_bug.cgi?id=2487465	Exploit, Issue Tracking, Third Party Advisory
0b0ca135-0b70-47e7-9f44-1890c2a1c46c	https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-47774.json	Third Party Advisory

Impacted products

Vendor	Product	Version
envoyproxy	envoy	*
envoyproxy	envoy	*
envoyproxy	envoy	*
envoyproxy	envoy	1.38.0
redhat	openshift_service_mesh	*
redhat	openshift_service_mesh	*
redhat	openshift_service_mesh	*
redhat	openshift_service_mesh	*
redhat	openshift_service_mesh	*

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "envoy",
          "vendor": "envoyproxy",
          "versions": [
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            {
              "status": "affected",
              "version": "\u003e= 1.37.0, \u003c 1.37.3"
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      "value": "Envoy is an open source edge and service proxy designed for cloud-native applications. Prior to versions 1.35.11, 1.36.7, 1.37.3, and 1.38.1, a vulnerability in Envoy\u0027s HTTP/2 downstream request processing allows an unauthenticated remote client to trigger excessive memory consumption, potentially resulting in OOM termination of the Envoy process and denial of service. The issue arises from the combination of two behaviors. First, cookie header bytes are not fully accounted for during request header size validation in Envoy. Second, HPACK header block limits in oghttp2/quiche are enforced on encoded bytes without a corresponding limit on total decoded header size. Together, these behaviors allow a malicious client to cause large decoded header allocations while bypassing the intended request header size protections. Versions 1.35.11, 1.36.7, 1.37.3, and 1.38.1 contain a fix. No complete workaround is known short of applying a fix. Possible temporary mitigations include disabling downstream HTTP/2 where operationally feasible; enforcing stricter request header and cookie limits before traffic reaches Envoy; and monitoring Envoy memory usage for abnormal growth under HTTP/2 traffic."
    },
    {
      "lang": "es",
      "value": "Envoy es un proxy de borde y de servicio de c\u00f3digo abierto dise\u00f1ado para aplicaciones nativas de la nube. Antes de las versiones 1.35.11, 1.36.7, 1.37.3 y 1.38.1, una vulnerabilidad en el procesamiento de solicitudes HTTP/2 descendentes de Envoy permite a un cliente remoto no autenticado activar un consumo excesivo de memoria, lo que podr\u00eda resultar en la terminaci\u00f3n OOM del proceso de Envoy y denegaci\u00f3n de servicio. El problema surge de la combinaci\u00f3n de dos comportamientos. Primero, los bytes del encabezado de la cookie no se contabilizan completamente durante la validaci\u00f3n del tama\u00f1o del encabezado de la solicitud en Envoy. Segundo, los l\u00edmites del bloque de encabezado HPACK en oghttp2/quiche se aplican a los bytes codificados sin un l\u00edmite correspondiente en el tama\u00f1o total del encabezado decodificado. Juntos, estos comportamientos permiten a un cliente malicioso causar grandes asignaciones de encabezados decodificados mientras elude las protecciones de tama\u00f1o de encabezado de solicitud previstas. Las versiones 1.35.11, 1.36.7, 1.37.3 y 1.38.1 contienen una correcci\u00f3n. No se conoce ninguna soluci\u00f3n alternativa completa que no sea aplicar una correcci\u00f3n. Las posibles mitigaciones temporales incluyen deshabilitar HTTP/2 descendente donde sea operacionalmente factible; aplicar l\u00edmites m\u00e1s estrictos para los encabezados de solicitud y las cookies antes de que el tr\u00e1fico llegue a Envoy; y monitorear el uso de memoria de Envoy para detectar un crecimiento anormal bajo tr\u00e1fico HTTP/2."
    }
  ],
  "id": "CVE-2026-47774",
  "lastModified": "2026-10-26T11:10:00.157",
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    "cvssMetricV31": [
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          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
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          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
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          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
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}

CVE-2026-47774 (GCVE-0-2026-47774)

Vulnerability from cvelistv5 – Published: 2026-06-17 16:58 – Updated: 2026-08-24 12:07

Title

Envoy vulnerable to HTTP/2 memory exhaustion via cookie header size bypass and HPACK amplification

Summary

Severity

7.5 (High)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

SSVC

Exploitation: none Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-06-17 18:00 UTC

CWE

CWE-405 - Asymmetric Resource Consumption (Amplification)
CWE-770 - Allocation of Resources Without Limits or Throttling
CWE-409 - Improper Handling of Highly Compressed Data (Data Amplification)

Assigner

GitHub_M CNA under the mitre root

CNA scorecard C 72/100 over 7926 records in the last 180 days details

References

10 references

URL	Tags
https://github.com/envoyproxy/envoy/security/advi…	x_refsource_CONFIRM
http://www.openwall.com/lists/oss-security/2026/0…
https://access.redhat.com/security/cve/CVE-2026-47774	vdb-entryx_refsource_REDHAT
https://bugzilla.redhat.com/show_bug.cgi?id=2487465	issue-trackingx_refsource_REDHAT
https://security.access.redhat.com/data/csaf/v2/v…	x_sadp-csaf-vex
https://access.redhat.com/errata/RHSA-2026:27114	vendor-advisoryx_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:26210	vendor-advisoryx_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:26222	vendor-advisoryx_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:26231	vendor-advisoryx_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:26247	vendor-advisoryx_refsource_REDHAT

Impacted products

6 products

Vendor	Product	Version
envoyproxy	envoy	Affected: < 1.35.11 Affected: >= 1.36.0, < 1.36.7 Affected: >= 1.37.0, < 1.37.3 Affected: >= 1.38.0, < 1.38.1
Red Hat	Red Hat OpenShift Service Mesh 2.6	Unaffected: 1781604724 , < * (rpm) cpe:/a:redhat:service_mesh:2.6::el9
Red Hat	Red Hat OpenShift Service Mesh 3.0	Unaffected: 1781069908 , < * (rpm) cpe:/a:redhat:service_mesh:3.0::el9
Red Hat	Red Hat OpenShift Service Mesh 3.1	Unaffected: 1781070158 , < * (rpm) cpe:/a:redhat:service_mesh:3.1::el9
Red Hat	Red Hat OpenShift Service Mesh 3.2	Unaffected: 1781070967 , < * (rpm) cpe:/a:redhat:service_mesh:3.2::el9
Red Hat	Red Hat OpenShift Service Mesh 3.3	Unaffected: 1781094520 , < * (rpm) cpe:/a:redhat:service_mesh:3.3::el9

Show details on NVD website

JSON

To clipboard

{
  "containers": {
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      {
        "providerMetadata": {
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          }
        ],
        "title": "CVE Program Container"
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        "metrics": [
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              "content": {
                "id": "CVE-2026-47774",
                "options": [
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                  },
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                  }
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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.

Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

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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.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

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