etcd: Authorization bypasses in multiple APIs

Description

etcd is a distributed key-value store for the data of a distributed system. Prior to versions 3.4.42, 3.5.28, and 3.6.9, unauthorized users may bypass authentication or authorization checks and call certain etcd functions in clusters that expose the gRPC API to untrusted or partially trusted clients. In unpatched etcd clusters with etcd auth enabled, unauthorized users are able to call MemberList and learn cluster topology, including member IDs and advertised endpoints; call Alarm, which can be abused for operational disruption or denial of service; use Lease APIs, interfering with TTL-based keys and lease ownership; and/or trigger compaction, permanently removing historical revisions and disrupting watch, audit, and recovery workflows. Kubernetes does not rely on etcd’s built-in authentication and authorization. Instead, the API server handles authentication and authorization itself, so typical Kubernetes deployments are not affected. Versions 3.4.42, 3.5.28, and 3.6.9 contain a patch. If upgrading is not immediately possible, reduce exposure by treating the affected RPCs as unauthenticated in practice. Restrict network access to etcd server ports so only trusted components can connect and/or require strong client identity at the transport layer, such as mTLS with tightly scoped client certificate distribution.

Scores

EPSS (exploitation in 30 days)

0.26% · top 82% of all CVEs (6 Nov 2026)

CISA SSVC

Exploitation: none · Automatable: yes · Technical impact: partial

The list uses the assigner's score when there is one, then CISA's, then NVD's: High 8.8.

Weakness

• CWE-862: Missing Authorization (opens in a new tab)All about CWE-862 and its CVEs

Affected products

• etcd-io · etcd

  • affected >= 3.6.0-alpha.0, < 3.6.9
  • affected >= 3.5.0-alpha.0, < 3.5.28
  • affected < 3.4.42

Affected packages

From reviewed advisories of the GitHub Advisory Database.

• Gogo.etcd.io/etcdGHSA-q8m4-xhhv-38mg (opens in a new tab)
• Gogo.etcd.io/etcd/v3GHSA-q8m4-xhhv-38mg (opens in a new tab)

References (1)

• https://github.com/etcd-io/etcd/security/advisories/GHSA-q8m4-xhhv-38mg (opens in a new tab)x_refsource_CONFIRM

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisory GHSA-q8m4-xhhv-38mg (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2026-33413](https://trackcve.app/badge/CVE-2026-33413.svg)](https://trackcve.app/cve/CVE-2026-33413)

Record last updated 26 Mar 2026, 18:51 UTC.