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Fencer Vulns
none 0.0

CVE-2026-33343 json

etcd: Nested etcd transactions bypass RBAC authorization checks

published 2026-03-20 7 mo ago modified 2026-09-10 1 mo ago also BIT-etcd-2026-33343 , EUVD-2026-20077 , GHSA-rfx7-8w68-q57q , GO-2026-4808

cvss
0.0
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 12%
public exploits
0
none known

Summary

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, an authenticated user with RBAC restricted permissions on key ranges can use nested transactions to bypass all key-level authorization. This allows any authenticated user with direct access to etcd to effectively ignore all key range restrictions, accessing the entire etcd data store. 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 require strong client identity at the transport layer, such as mTLS with tightly scoped client certificate distribution.

Patch / fix

  • go go.etcd.io/etcd/v3 3.4.42, 3.5.28, 3.6.9
  • bitnami etcd 3.4.42, 3.5.28, 3.6.9
  • etcd etcd 3.4.42, 3.5.28, 3.6.9
  • etcd Debian 14 3.5.16-11

debian advisories DEBIAN-CVE-2026-33343

  • govulncheck-vulndb openSUSE Leap 16.0 0.0.20260723T184607-160000.1.1

opensuse advisories openSUSE-SU-2026:21483-1

  • etcd Alpine 3.24, Alpine 3.23 3.6.10-r0

alpine advisories ALPINE-CVE-2026-33343

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • etcd Azure Linux 3.0 3.5.28-1

azure linux advisories AZL-80954

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-33343 updated cvss 6.5

etcd: etcd: Authorization bypass allows information disclosure via nested transactions

  • Red Hat OpenStack Platform 16.2 etcd Red Hat OpenStack Platform 17.1 etcd
    affected: workaround, no fix available “Fix deferred”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
7 mo ago

Exploit prediction

0.22% chance of exploitation in the next 30 days, higher than 12% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 0.0 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:N
GitHub 3.1 0.0 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:N
NVD 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
OSV 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

Affected packages

ecosystem package affected fixed in
go go.etcd.io/etcd/v3
>=3.6.0-alpha.0, <3.6.9
>=3.5.0-alpha.0, <3.5.28
<3.4.42
3.6.9
3.5.28
3.4.42
go go.etcd.io/etcd
<=3.3.27
all versions
 no fix listed
bitnami etcd
<3.4.42
>=3.5.0, <3.5.28
>=3.6.0, <3.6.9
3.4.42
3.5.28
3.6.9

Affected products

  • etcd-io etcd

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.