CVE-2021-25741
A public proof of concept exists; no exploitation attested.
- Published2021-09-20
- WeaknessCWE-20 · CWE-552
Am I affected?
Debian, Ubuntu or Red Hat sometimes backport a fix without changing the upstream version number: such a version reads « to verify », never « affected ».With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.
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.
Timeline
dates in UTC- 2021-09-2017:15CVE publishedNVD
- 2026-10-2319:23First public proof of conceptPoC-in-GitHub
Observed activity
isMalicious corpus · updated 2026-10-23 18:48 UTCBlock these indicators
- Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-25741?format=txt
- CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-25741?format=csv
- TAXII collection of exploited CVEs
- The EDL and CSV take an API key on the Pro plan.
Versions per branch
NVD · CISA-ADP| Branch | Affected | Fixed in | Source |
|---|---|---|---|
| 1.19 | ≤ 1.19.14 | no fix published | NVD · CISA-ADP |
| 1.20 | ≥ 1.20.0, ≤ 1.20.10 | no fix published | NVD · CISA-ADP |
| 1.21 | ≥ 1.21.0, ≤ 1.21.4 | no fix published | NVD · CISA-ADP |
| 1.22 | ≥ 1.22.0, ≤ 1.22.1 | no fix published | NVD · CISA-ADP |
as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.
Fix
Advisories and patches
- github.comMitigation
- groups.google.comMitigation
Detection
read 2026-10-23 19:23 UTC- Nuclei template
- none so far ProjectDiscovery
- Exploit-DB
- no entry Exploit-DB
- Proof-of-concept repositories
- 3 repositories, unverifiedBetep0k/CVE-2021-25741cdxiaodong/CVE-2021-25741Glutenfree69/ZigRaceExploit PoC-in-GitHub
Sources
- CISA-ADPSSVC decisionnone2024-08-20
- OpenCVESSVC decisionnone—
- CNACVSS 3.18.8read 2026-10-23
- NVDCVSS 3.18.1read 2026-10-23
- NVDCVSS 2.05.5read 2026-10-23
- CNAweakness (CWE)CWE-20read 2026-10-23
- NVDweakness (CWE)CWE-552read 2026-10-23
- FIRST EPSSEPSS score8.0 %2026-10-22
- PoC-in-GitHubproof of concept3read 2026-10-23
Technical details
- CVSS v3 Vector
- CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
- Published
- 2021-09-20
- Last Modified
- 2026-06-17
- NVD status
- Modified
Frequently asked questions
What is CVE-2021-25741?
Is CVE-2021-25741 actively exploited?
What is the CVSS score for CVE-2021-25741?
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