Vulnerability in Elastic Apm Server
CVE-2026-78594
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 4.9 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.005 (41.5th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 41st percentile — 41.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.005 · change: +0.002
Affected products
- Elastic Apm Server — versions 9.5.0
- Elastic Apm Server — versions 9.5.0
Weakness classification (CWE)
References
- discuss.elastic.co/t/apm-server-8-19-20-9-4-5-9-5-1-security-update-esa-2026-15… (Mitigation, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-78594?
- CVE-2026-78594 is a medium-severity vulnerability in Elastic Apm Server, classified under Improper Handling of Highly Compressed Data (Data Amplification). CVSS score: 4.9/10. Published 2026-09-02.
- How severe is CVE-2026-78594?
- Medium severity. CVSS v3 base score is 4.9 out of 10.