How severe is CVE-2026-73499?

No CVSS score has been assigned to CVE-2026-73499 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-73499?

CVE-2026-73499 affects the following packages: go.etcd.io/etcd/v3 (Go), go.etcd.io/etcd/v3 (Go), go.etcd.io/etcd/v3 (Go). Ecosystems affected: Go.

How do I fix CVE-2026-73499?

Update go.etcd.io/etcd/v3 to 3.7.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-73499 is resolved across your whole dependency graph.

How do I detect CVE-2026-73499 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-2026-73499 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-2026-73499 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-73499 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-2026-73499?

CVE-2026-73499 has an EPSS (Exploit Prediction Scoring System) score of 0.7%, placing it in the 50th 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-2026-73499?

CVE-2026-73499 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-2026-73499 published, and has it been updated?

CVE-2026-73499 was published on August 12, 2026 and was last updated on September 20, 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

CVE-2026-73499 — v3

Fix: etcd-io/etcd@6643f80

CVE-2026-73499 is a 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: Watch API authorization bypass via open-ended range requests

Also known asBIT-etcd-2026-73499GHSA-xg4h-6gfc-h4m8GO-2026-6114

Published

Aug 12, 2026

Updated

Sep 20, 2026

Affected

3 pkgs

Patched

3 / 3

Exploits

None indexed

Exploitation data as of Sep 26, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

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-2026-73499.

EPSS Exploitation Probability

via FIRST.org ↗

0.7%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs50th percentile — riskier than 50% of all scored CVEsHighest risk

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

Real-World Exposure

3 pkgs affected

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

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?

A user granted READ permission on a single, exact key can use the Watch gRPC API with clientv3.WithFromKey() (an open-ended, "from this key to the end of the keyspace" watch) to receive watch events for every key lexicographically greater than or equal to their permitted key — not just the one key they were granted.

This is an authorization bypass in etcd's RBAC enforcement for the Watch API; Range/Get and DeleteRange requests are not affected. It only affects clusters with authentication enabled — clusters running without auth already allow unrestricted read access.

Patches

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

This vulnerability is patched in the following versions:

etcd 3.7.1
etcd 3.6.14
etcd 3.5.33

Workarounds

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

If upgrading is not immediately possible, the following mitigations reduce exposure:

Audit READ grants. Any READ grant — even on one key — can be leveraged via Watch to read everything after it. Review who holds READ permissions and revoke/tighten any you wouldn't trust with full read access.
Restrict network access. Limit which hosts can reach etcd's client (gRPC) port via firewall rules or network policy, reducing who can attempt exploitation.

Reporter

Luis Toro (@lobuhi on Github)
Anthropic and Adam Korczynski (@AdamKorcz on Github)

Affected Packages

3 total 3 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`go.etcd.io/etcd/v3`	≥ 3.7.0-alpha.0&&< 3.7.1	3.7.1`go get go.etcd.io/etcd/v3@v3.7.1`
🐹Go	`go.etcd.io/etcd/v3`	≥ 3.6.0&&< 3.6.14	3.6.14`go get go.etcd.io/etcd/v3@v3.6.14`
🐹Go	`go.etcd.io/etcd/v3`	all versions	3.5.33`go get go.etcd.io/etcd/v3@v3.5.33`

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 3.7.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-73499 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

A flaw was found in etcd's Watch gRPC API. A user with READ permission on a single key can use open-ended range requests to bypass RBAC authorization and receive watch events for keys beyond their authorized scope, leading to information disclosure. This issue only affects etcd clusters with authentication enabled.

Workaround published by Red Hat

If etcd authentication is not required for the deployment, this vulnerability does not apply. For clusters with authentication enabled, restrict network-level access to the etcd gRPC API to trusted clients only, and audit user permissions to ensure the principle of least privilege.

Source: Red Hat security advisory for CVE-2026-73499 (CC BY 4.0)

Frequently Asked Questions

### Impact _What kind of vulnerability is it? Who is impacted?_ A user granted READ permission on a single, exact key can use the Watch gRPC API with `clientv3.WithFromKey()` (an open-ended, "from this key to the end of the keyspace" watch) to receive watch events for every key lexicographically greater than or equal to their permitted key — not just the one key they were granted. This is an authorization bypass in etcd's RBAC enforcement for the Watch API; Range/Get and DeleteRange requests are not affected. It only affects clusters with authentication enabled — clusters running without au