High severity · published Jan 26, 2026
CVE-2025-27821
HDFS native client: Out of bounds write in URI parser of native HDFS client
7.3
CVSS
0.9%
EPSS
No
On KEV
Description
Out-of-bounds Write vulnerability in Apache Hadoop HDFS native client.
This issue affects Apache Hadoop: from 3.2.0 before 3.4.2.
Users are recommended to upgrade to version 3.4.2, which fixes the issue.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
Low
Integrity
Low
Availability
Low
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.9% · higher than 60% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
HN
HDFS native client · Apache Software Foundation
3.2.0 before 3.4.2 · source: vendor
HA
Hadoop · Apache
3.2.0 before 3.4.2 · source: NVD