How severe is CVE-2026-33343?

CVE-2026-33343 has a CVSS score of 0/10, rated NONE. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2026-33343?

CVE-2026-33343 affects the following packages: go.etcd.io/etcd/v3 (Go), go.etcd.io/etcd/v3 (Go), go.etcd.io/etcd/v3 (Go), go.etcd.io/etcd (Go). Ecosystems affected: Go.

How do I fix CVE-2026-33343?

Update go.etcd.io/etcd/v3 to 3.6.9 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-33343 is resolved across your whole dependency graph.

How do I detect CVE-2026-33343 in my Go dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for go.etcd.io/etcd/v3, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-33343 if there is no patch (or I can't update yet)?

Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.

Is CVE-2026-33343 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-33343 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-33343?

CVE-2026-33343 has an EPSS (Exploit Prediction Scoring System) score of 0.2%, placing it in the 12th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-33343?

CVE-2026-33343 is classified as CWE-863 (CWE-863). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-33343 published, and has it been updated?

CVE-2026-33343 was published on March 26, 2026 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐹

🐹 Go

Not in CISA KEV

NONE severity

CVE-2026-33343 — etcd

NONE

CVE-2026-33343 is a none-severity (CVSS 0) CWE-863 vulnerability in go.etcd.io/etcd/v3. A fix is available for go.etcd.io/etcd/v3 — see the affected versions and patch details below.

etcd: Nested etcd transactions bypass RBAC authorization checks

Also known asBIT-etcd-2026-33343GHSA-rfx7-8w68-q57qGO-2026-4808

Published

Mar 26, 2026

Updated

Oct 28, 2026

Affected

4 pkgs

Patched

3 / 4

Exploits

None indexed

Exploitation data as of Nov 7, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-33343.

EPSS Exploitation Probability

via FIRST.org ↗

0.2%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs12th percentile — riskier than 12% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

4 pkgs affected

🐹go.etcd.io/etcd/v3🐹go.etcd.io/etcd/v3🐹go.etcd.io/etcd/v3🐹go.etcd.io/etcd

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.

Description

Impact

What kind of vulnerability is it? Who is impacted?

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.

Patches

Has the problem been patched? What versions should users upgrade to?

This vulnerability is patched in the following versions:

etcd 3.6.9
etcd 3.5.28
etcd 3.4.42

Workarounds

Is there a way for users to fix or remediate the vulnerability without upgrading?

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
require strong client identity at the transport layer, such as mTLS with tightly scoped client certificate distribution

Reporters

Our community helps keep etcd secure

SIG-Etcd thanks community members Luke Francis and Battulga Byambaa for reporting this vulnerability.

Affected Packages

4 total 3 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`go.etcd.io/etcd/v3`	≥ 3.6.0-alpha.0&&< 3.6.9	3.6.9`go get go.etcd.io/etcd/v3@v3.6.9`
🐹Go	`go.etcd.io/etcd/v3`	≥ 3.5.0-alpha.0&&< 3.5.28	3.5.28`go get go.etcd.io/etcd/v3@v3.5.28`
🐹Go	`go.etcd.io/etcd/v3`	all versions	3.4.42`go get go.etcd.io/etcd/v3@v3.4.42`
🐹Go	`go.etcd.io/etcd`	all versions	No fix

Affected Products

1 product · 3 configurations

Application

etcdetcd

≥ 3.6.0 && < 3.6.9

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for go.etcd.io/etcd/v3, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update go.etcd.io/etcd/v3 to 3.6.9 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-33343 is resolved across your whole dependency graph.
Workarounds
Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatModerate

Workaround published by Red Hat

To reduce exposure, restrict network access to etcd server ports, ensuring only trusted components can connect. Additionally, implement strong client identity at the transport layer, such as mTLS with tightly scoped client certificate distribution. This limits direct access to the etcd data store, which is a prerequisite for exploiting this vulnerability. If etcd is configured to reload, a service restart may be required for these changes to take effect.

Source: Red Hat security advisory for CVE-2026-33343 (CC BY 4.0)

Frequently Asked Questions

### Impact _What kind of vulnerability is it? Who is impacted?_ 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. ### Patches _Has the problem been patched