CVE-2026-47774

Published Jun 17, 2026

Last updated 3 days ago

CVSS high 7.5

Server

Overview

Description: 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.
Source: security-advisories@github.com
NVD status: Analyzed
Products: envoy, openshift_service_mesh

Risk scores

CVSS 3.1

Type: Secondary
Base score: 7.5
Impact score: 3.6
Exploitability score: 3.9
Vector string: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Severity: HIGH

Weaknesses

security-advisories@github.com: CWE-405
0b0ca135-0b70-47e7-9f44-1890c2a1c46c: CWE-409

Hype score: Not currently trending

Configurations

[
  {
    "nodes": [
      {
        "cpeMatch": [
          {
            "criteria": "cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*",
            "matchCriteriaId": "F7228260-24CC-44ED-8805-D913C775F342",
            "versionEndExcluding": "1.35.11",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*",
            "matchCriteriaId": "C0A19272-7178-4FCE-A4D3-5E578A871D4D",
            "versionEndExcluding": "1.36.7",
            "versionStartIncluding": "1.36.0",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*",
            "matchCriteriaId": "24F12FF2-A40F-4C2C-B9C4-F59A22B99843",
            "versionEndExcluding": "1.37.3",
            "versionStartIncluding": "1.37.0",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:a:envoyproxy:envoy:1.38.0:*:*:*:*:*:*:*",
            "matchCriteriaId": "8AD655E3-C12A-42B5-948D-442C6AF3469D",
            "vulnerable": true
          }
        ],
        "negate": false,
        "operator": "OR"
      }
    ]
  },
  {
    "nodes": [
      {
        "cpeMatch": [
          {
            "criteria": "cpe:2.3:a:redhat:openshift_service_mesh:*:*:*:*:*:*:*:*",
            "matchCriteriaId": "FFD517BC-CA76-4E2B-BDA5-60A9A2E35183",
            "versionEndExcluding": "2.6.17",
            "versionStartIncluding": "2.6",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:a:redhat:openshift_service_mesh:*:*:*:*:*:*:*:*",
            "matchCriteriaId": "6236CEDD-4A16-4232-97FE-59BBA2F639C1",
            "versionEndExcluding": "3.0.12",
            "versionStartIncluding": "3.0",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:a:redhat:openshift_service_mesh:*:*:*:*:*:*:*:*",
            "matchCriteriaId": "B8A5586D-5F6B-48E9-B0E7-66A2C53272DF",
            "versionEndExcluding": "3.1.9",
            "versionStartIncluding": "3.1",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:a:redhat:openshift_service_mesh:*:*:*:*:*:*:*:*",
            "matchCriteriaId": "9F44E8AD-F96C-4083-ADA4-6E8F93FA4149",
            "versionEndExcluding": "3.2.6",
            "versionStartIncluding": "3.2",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:a:redhat:openshift_service_mesh:*:*:*:*:*:*:*:*",
            "matchCriteriaId": "9EDC21C9-C155-4A6E-8EFA-47CD399312D4",
            "versionEndExcluding": "3.3.4",
            "versionStartIncluding": "3.3",
            "vulnerable": true
          }
        ],
        "negate": false,
        "operator": "OR"
      }
    ]
  }
]

References

Sources include official advisories and independent security research.

Overview

Risk scores

CVSS 3.1

Weaknesses

Social media

Configurations

Related CVEs

References