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NVD / CVE Program· CNA GitHub_M

CVE-2026-33343: etcd: Nested etcd transactions bypass RBAC authorization checks

Noroxi assessment

Priority: Monitor (action score 26/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.21% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • Fixed version: azl3 etcd 3.5.21-1 on Azure Linux 3.0 3.5.28-1; cbl2 etcd 3.5.21-4 on CBL Mariner 2.0 3.5.28-1.
  • Severity is disputed: the assigning authority (CNA) scores it 0.0, NVD 6.5.

Low priority for now. Upgrade to azl3 etcd 3.5.21-1 on Azure Linux 3.0 3.5.28-1; cbl2 etcd 3.5.21-4 on CBL Mariner 2.0 3.5.28-1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

MediumCVSS 6.5 · v3.1—No exploit Fix available
Published
Mar 26, 2026
Updated
Jun 17, 2026
EPSS
0.2% · 12th percentile

Report tools

JSON

Action score

26

Monitor

Low priority for now.

CVSS
26 / 40 · 6.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CISA SSVC decision

Exploitation
none
Automatable
yes
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
6.5
CNA · GitHub_M
0.0
6.5 point gap

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

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-33343

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
etcdetcd

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • etcd etcdbefore 3.4.42
  • etcd etcd3.5.0 and later · before 3.5.28
  • etcd etcd3.6.0 and later · before 3.6.9

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

  • etcd-io etcd

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

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Alpine:v3.23etcdfrom 3.5.0 · before 3.6.10-r03.6.10-r0
Debian:12etcdfrom 0—
Debian:14etcdbefore 3.5.16-113.5.16-11
Gogo.etcd.io/etcdfrom 0—
Gogo.etcd.io/etcdup to and including 3.3.27—
Gogo.etcd.io/etcd/v3from 3.5.0-alpha.0 · before 3.5.283.5.28
Gogo.etcd.io/etcd/v3from 3.6.0-alpha.0 · before 3.6.93.6.9
Gogo.etcd.io/etcd/v3before 3.4.423.4.42

Same product

etcd: all records

Other highest-scoring records for the same primary product.

  • CVE-2021-28235Authentication vulnerability found in Etcd-io v.3.4.10 allows remote attackers to escalate privileges via the debug function.
    39Monitor
  • CVE-2026-33413etcd: Authorization bypasses in multiple APIs
    35Monitor
  • CVE-2018-16886etcd versions 3.2.x before 3.2.26 and 3.3.x before 3.3.11 are vulnerable to an improper authentication issue when role-based access control
    33Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2023-32082May 11, 2023 · etcd key name can be accessed via LeaseTimeToLive API
    17Monitor
  • ← EarlierCVE-2022-34038Aug 22, 2023 · Etcd v3.5.4 allows remote attackers to cause a denial of service via function PageWriter.write in pagewriter.go.
    31Monitor
  • Later →CVE-2026-44283May 14, 2026 · etcd: Read access via PrevKv in etcd transactions may bypass RBAC authorization checks
    17Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
azl3 etcd 3.5.21-1 on Azure Linux 3.03.5.28-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
cbl2 etcd 3.5.21-4 on CBL Mariner 2.03.5.28-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
alpine:etcd3.6.10-r0 · Alpine:v3.23Package registry (OSV)
debian:etcd3.5.16-11 · Debian:14Package registry (OSV)
Go:go.etcd.io/etcd/v33.4.42Package registry (OSV)
Go:go.etcd.io/etcd/v33.5.28Package registry (OSV)
Go:go.etcd.io/etcd/v33.6.9Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2026-4428349 days apartetcd: Read access via PrevKv in etcd transactions may bypass RBAC authorization checks
    17Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
none
Availability
none
Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
None
Availability impact
None

Weakness class (CWE)

CWE-863 · Incorrect Authorization

CVSS vector

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

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records