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Fencer Vulns
critical 9.8

CVE-2021-28235 json

Etcd-io Improper Authentication vulnerability

published 2023-04-04 3 y ago modified 2026-07-09 4 mo ago also BIT-etcd-2021-28235 , EUVD-2023-1310 , GHSA-gmph-wf7j-9gcm

cvss
9.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.6%
EPSS 1.6% chance of exploitation in 30 days, percentile 76%
public exploits
0
none known

Summary

Authentication vulnerability found in Etcd-io v.3.4.10 allows remote attackers to escalate privileges via the debug function.

Patch / fix

  • bitnami etcd 3.4.11
  • etcd Debian 14, Debian 13 3.4.30-1

debian advisories DEBIAN-CVE-2021-28235

  • etcd Ubuntu Pro 18.04 LTS 3.2.17+dfsg-1ubuntu0.1+esm2
  • etcd Ubuntu Pro 20.04 LTS 3.2.26+dfsg-6ubuntu0.2+esm1
  • etcd Ubuntu Pro 22.04 LTS 3.3.25+dfsg-7ubuntu0.22.04.1+esm1

ubuntu advisories UBUNTU-CVE-2021-28235

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • etcd openstack 16.2, openstack 16.1 3.3.23-14.el8ost
  • etcd openstack 17.0 3.4.26-1.el9ost

red hat advisories RHSA-2023:3447RHSA-2023:3445RHSA-2023:3441

  • etcd openSUSE Leap 15.6, openSUSE Leap 15.5 3.5.12-150000.7.6.1

suse advisories SUSE-SU-2024:3656-1

  • etcd Package Hub 15 SP6, openSUSE Leap 15.6 3.5.12-bp156.4.3.1
  • etcd openSUSE Tumbleweed 3.5.8-1.1
  • etcd-for-k8s1.25 openSUSE Tumbleweed 3.5.9-1.1
  • etcd-for-k8s1.26 openSUSE Tumbleweed 3.5.9-1.1
  • etcd-for-k8s1.27 openSUSE Tumbleweed 3.5.9-1.1

opensuse advisories openSUSE-SU-2025:0003-1openSUSE-SU-2024:12896-1openSUSE-SU-2024:13369-1openSUSE-SU-2024:13370-1openSUSE-SU-2024:13371-1

  • etcd CBL-Mariner 2.0 3.5.4-6

azure linux advisories AZL-26139

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-2021-28235 updated cvss 9.8

etcd: Information discosure via debug function

  • Red Hat Logging Subsystem for Red Hat OpenShift openshift-logging/lokistack-gateway-rhel8
    affected: no fix available
  • Red Hat Enterprise Linux 7 etcd, etcd3
    affected: no fix planned “Will not fix”
  • Red Hat OpenShift Container Platform 4 openshift4/ose-etcd, openshift4/ose-docker-builder, openshift4/ose-operator-sdk-rhel8, openshift4/ose-machine-config-operator, openshift-security-profiles-operator-container Red Hat Storage 3 etcd
    affected: no fix available
  • Red Hat OpenStack Platform 16.1 etcd 3.3.23-14.el8ost
    fixed: vendor fix RHSA-2023:3447
  • Red Hat OpenStack Platform 16.2 etcd 3.3.23-14.el8ost
    fixed: vendor fix RHSA-2023:3445
  • Red Hat OpenStack Platform 17.0 etcd 3.4.26-1.el9ost
    fixed: vendor fix RHSA-2023:3441
  • Red Hat OpenShift Serverless openshift-serverless-1/client-kn-rhel8
    not affected: vulnerable code not present

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
total
Assessed
20 mo ago

Exploit prediction

1.62% chance of exploitation in the next 30 days, higher than 76% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
GitHub 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
OSV 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
go go.etcd.io/etcd/v3
1 listed version
 no fix listed
bitnami etcd
>=3.4.10, <3.4.11
3.4.11

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.