Medium severity · published Sep 2, 2026
CVE-2026-78594
Improper Handling of Highly Compressed Data in APM Server Leading to Persistent Denial of Service
4.9
CVSS
0.5%
EPSS
No
On KEV
Description
Improper Handling of Highly Compressed Data (CWE-409) in APM Server can lead to a persistent denial of service via Excessive Allocation (CAPEC-130). An authenticated user with write access to source map content could store specially crafted, highly compressed content that exhausts the memory available to APM Server when it is later processed, terminating the process. The condition recurs on every restart until the stored content is removed.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
High
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 43% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
AS
Apm Server · Elastic
8.0.0 through 8.19.19; 9.0.0 through 9.4.4; 9.5.0 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-78594
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-78594
Vendor Advisory
https://discuss.elastic.co/t/apm-server-8-19-20-9-4-5-9-5-1-security-update-esa-2026-152/390110
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