Vulnerability · Published Sep 20, 2021 · Assigned by kubernetes
CVE-2021-25740Holes in EndpointSlice Validation Enable Host Network Hijack
Low 3.1
In plain English
A low-severity security flaw in Kubernetes from Kubernetes. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 2.0% (higher than 80% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 3.1)3.1Low
Exploit odds (30 days)2.0%top 19.7% of all CVEs
Exploited in the wildNo reportsnot in CISA KEV
Attack toolingNoneno public tooling known
Official description
A security issue was discovered with Kubernetes that could enable users to send network traffic to locations they would otherwise not have access to via a confused deputy attack.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | kubernetes | 1.20.5+really1.20.2-1 | DEBIAN-CVE-2021-25740 |
| Debian:13 | kubernetes | 1.20.5+really1.20.2-1 | DEBIAN-CVE-2021-25740 |
| Debian:14 | kubernetes | 1.20.5+really1.20.2-1 | DEBIAN-CVE-2021-25740 |
| Go | k8s.io/kubernetes | no fix listed | GHSA-vw47-mr44-3jf9 |
| Ubuntu:22.04:LTS | kubernetes | no fix listed | UBUNTU-CVE-2021-25740 |
| Ubuntu:24.04:LTS | kubernetes | no fix listed | UBUNTU-CVE-2021-25740 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Kubernetes | Kubernetes | 0 – before * |
Weakness: CWE-441 · Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N
References
- https://kubernetes.io/blog/2026/05/26/reconciling-unfixed-kubernetes-cves/ x_refsource_MISC
- https://groups.google.com/g/kubernetes-security-announce/c/WYE9ptrhSLE x_refsource_MISC
- https://github.com/kubernetes/kubernetes/issues/103675 x_refsource_MISC
- https://security.netapp.com/advisory/ntap-20211014-0001/ x_refsource_CONFIRM