Improper handling of highly compressed data in APM Server - CVE-2026-78594
Published: September 2, 2026
Vulnerability identifier: #VU146675
CSH Severity: Low
CVSS v4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-78594
CWE-ID: CWE-409
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote user to cause a denial of service.
The vulnerability exists due to improper handling of highly compressed data in source map processing in APM Server when processing stored source map content. A remote privileged user can store specially crafted, highly compressed content to cause a denial of service.
The condition recurs on every restart until the stored content is removed. Only instances with real user monitoring enabled and source map fetching configured are vulnerable.
Affected software
APM Server
How to mitigate CVE-2026-78594
Install security update from vendor's website.
APM Server - addressed in versions 8.19.20, 9.4.5, 9.5.1