CVE-2026-78594 Improper Handling of Highly Compressed Data in APM Server Leading to Persistent Denial of Service

Medium 4.9 Published 2 Sep 2026 Updated 2 Sep 2026

An authenticated user can cause persistent denial of service in Elastic APM Server by uploading highly compressed source maps that exhaust memory.

Exploited in the wild: Not known
Login needed: An administrator
Attackable: Over the internet
Victim action needed: Not needed
Fix: None listed

What is CVE-2026-78594?

CVE-2026-78594 is a medium-severity denial of service vulnerability in Elastic Apm Server, published on 2 Sep 2026. An attacker needs administrator access to exploit it, with no action from the victim.

Official 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.

Weakness: CWE-409

Which versions are affected by CVE-2026-78594?

It affects 1 product.

Products include Elastic Apm Server.

How do I fix CVE-2026-78594?

No fix has been published for CVE-2026-78594 yet. Limit exposure of the affected software until one is available.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2026-78594 being exploited?

There is no known exploitation of CVE-2026-78594 in the wild and no public exploit code.

Sources

Also known as GHSA-5jf2-hccc-p8fm.