Public proof of conceptFix available

CVE-2021-25642

Q: Is CVE-2021-25642 actively exploited?

Active exploitation of CVE-2021-25642 has not been confirmed. Its EPSS score was 2.3% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

Q: What is the CVSS score for CVE-2021-25642?

CVE-2021-25642 has a CVSS v3 base score of 8.8 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

A public proof of concept exists; no exploitation attested.

Published2022-08-25
Fixed in3.3.4 · 3.2.4 · 2.10.2
WeaknessCWE-502

Am I 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

ZKConfigurationStore which is optionally used by CapacityScheduler of Apache Hadoop YARN deserializes data obtained from ZooKeeper without validation. An attacker having access to ZooKeeper can run arbitrary commands as YARN user by exploiting this. Users should upgrade to Apache Hadoop 2.10.2, 3.2.4, 3.3.4 or later (containing YARN-11126) if ZKConfigurationStore is used.

Timeline

dates in UTC

2022-08-2514:15CVE publishedNVD
2026-10-2319:23First public proof of conceptPoC-in-GitHub

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-25642?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-25642?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

Apache hadoop

Branch	Affected	Fixed in	Source
3.3	≥ 3.3.0, < 3.3.4	3.3.4	NVD
3.x	≥ 3.0.0, < 3.2.4	3.2.4	NVD
2.x	≥ 2.9.0, < 2.10.2	2.10.2	NVD

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

Update Apache hadoop to 3.3.4 · 3.2.4 · 2.10.2

Advisories and patches

lists.apache.orgVendor Advisory

Detection

read 2026-10-23 19:23 UTC

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: 1 repository, unverifiedsafe3s/CVE-2021-25642

Sources

NVDCVSS 3.18.8read 2026-10-23
CNAweakness (CWE)CWE-502read 2026-10-23
NVDweakness (CWE)CWE-502read 2026-10-23
FIRST EPSSEPSS score2.3 %2026-10-22
PoC-in-GitHubproof of concept1read 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:H
Published: 2022-08-25
Last Modified: 2026-06-17
NVD status: Modified

Frequently asked questions

What is CVE-2021-25642?

Is CVE-2021-25642 actively exploited?

Active exploitation of CVE-2021-25642 has not been confirmed. Its EPSS score was 2.3% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-25642?

CVE-2021-25642 has a CVSS v3 base score of 8.8 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

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