Vulnerability · Published Sep 20, 2021 · Assigned by kubernetes
CVE-2021-25741Symlink Exchange Can Allow Host Filesystem Access
High 8.8
In plain English
A high-severity improper input validation 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 8.0% (higher than 95% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code. Fixed versions are available - upgrade the affected package.
Severity (CVSS 3.1)8.8High
Exploit odds (30 days)8.0%top 5.2% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack tooling1Public PoC
Official description
A security issue was discovered in Kubernetes where a user may be able to create a container with subpath volume mounts to access files & directories outside of the volume, including on the host filesystem.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | kubernetes | 1.20.5+really1.20.2-1 | DEBIAN-CVE-2021-25741 |
| Debian:13 | kubernetes | 1.20.5+really1.20.2-1 | DEBIAN-CVE-2021-25741 |
| Debian:14 | kubernetes | 1.20.5+really1.20.2-1 | DEBIAN-CVE-2021-25741 |
| Go | k8s.io/kubernetes | 1.19.15 | GHSA-f5f7-6478-qm6p |
| Go | k8s.io/kubernetes | 1.20.11 | GHSA-f5f7-6478-qm6p |
| Go | k8s.io/kubernetes | 1.21.5 | GHSA-f5f7-6478-qm6p |
| Go | k8s.io/kubernetes | 1.22.2 | GHSA-f5f7-6478-qm6p |
| Go | k8s.io/kubernetes | 1.19.15, 1.20.11, 1.21.5, 1.22.2 | GO-2022-0910 |
| Ubuntu:22.04:LTS | kubernetes | no fix listed | UBUNTU-CVE-2021-25741 |
| Ubuntu:24.04:LTS | kubernetes | no fix listed | UBUNTU-CVE-2021-25741 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Kubernetes | Kubernetes | unspecified – through 1.19.14unspecified – through 1.20.10unspecified – through 1.21.4unspecified – through 1.22.1 |
Weakness: CWE-20 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
References
- https://groups.google.com/g/kubernetes-security-announce/c/nyfdhK24H7s x_refsource_MISC
- https://github.com/kubernetes/kubernetes/issues/104980 x_refsource_MISC
- https://security.netapp.com/advisory/ntap-20211008-0006/ x_refsource_CONFIRM