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Fencer Vulns
medium 6.5

CVE-2026-72687 json

Memory Allocation with Excessive Size Value in Elasticsearch Leading to Denial of Service

published 2026-08-13 2 mo ago modified 2026-09-08 2 mo ago also BIT-elasticsearch-2026-72687 , EUVD-2026-58251

cvss
6.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 36%
public exploits
0
none known

Summary

A flaw in Elasticsearch allows a low-privileged authenticated user to submit a single small request containing a forged opaque identifier. Elasticsearch decodes and deserializes the identifier before confirming that it was legitimately issued by the cluster, and a size value carried inside the identifier drives an allocation that is neither capped nor accounted for by the available memory-usage controls. The resulting out-of-memory condition is fatal and terminates the affected node process, resulting in a denial of service.

Patch / fix

  • bitnami elasticsearch 8.19.20, 9.4.5, 9.5.1
  • elastic elasticsearch 8.19.20, 9.4.5, 9.5.1
  • elasticsearch elasticsearch 8.19.20, 9.4.5, 9.5.1
  • org.elasticsearch elasticsearch 8.19.20, 9.4.5, 9.5.1

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
2 mo ago

Exploit prediction

0.42% chance of exploitation in the next 30 days, higher than 36% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
OSV 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
bitnami elasticsearch
>=8.0.0, <8.19.20
>=9.0.0, <9.4.5
>=9.5.0, <9.5.1
8.19.20
9.4.5
9.5.1

Affected products

  • Elastic Elasticsearch

Classification

Weakness
  • CWE-789 Memory Allocation with Excessive Size Value

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.