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Back to active CVEs
Medium · CVSS 4.9CVE-2026-78594

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

Answer in brief

CVE-2026-78594 records a Medium severity (CVSS 4.9) vulnerability in Improper Handling of Highly Compressed Data in APM Server Leading to Persistent Denial of Service. The current sources do not mark it as known exploited. The current feed maps Elastic/Apm Server (generic), Elastic/Apm Server (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 2, 2026Updated Sep 3, 2026Source checked Oct 17, 2026First seen by HOL Sep 2, 2026Material review Sep 3, 2026
Upstream Advisory

Key facts

Risk
Medium · CVSS 4.9
Exploitation
Not marked as known exploited
Affected software
4 mapped packages or products
Fix availability
Not reported

Why this deserves its current priority

CVSS is 4.9. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Elastic/Apm Server (generic), Elastic/Apm Server (generic). Check affected ranges and fixed versions before updating.

Affected products and reported versions
ProductAffected versionsFixed versions
cpe:2.3:a:elastic:apm_server:*:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:a:elastic:apm_server:9.5.0:*:*:*:*:*:*:*Not reportedNot reported
Mapped affected packages and fixed versions
PackageAffected rangeFixed version
Elastic/Apm Servergeneric8.0.0 || 9.0.0 || 9.5.0Not reported
Elastic/Apm Servergeneric>=8.0.0 <=8.19.19 || >=9.0.0 <=9.4.4 || 9.5.0Not reported

Recommended response

  1. 1Check inventory. Check lockfiles and deployed manifests for Elastic/Apm Server, Elastic/Apm Server.
  2. 2Review the reported fix. Monitor this advisory for an available fix and review any installs of the affected package.

Evidence timeline and material changes

  1. Published upstream

    Sep 2, 2026

    Evidence: source:cvelist:source_dates:source-dates:record

  2. Source modified

    Sep 3, 2026

    Evidence: source:cvelist:source_dates:source-dates:record

  3. First seen by HOL

    Sep 2, 2026

Sources and claim methodology

  • Source referencediscuss.elastic.co
Upstream source 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.

Quoted source text, attributed separately from HOL analysis.

Related CVEs

  • Fleet before 4.83.0 Denial of Service via Unbounded Gzip DecompressionAlso CWE-409
  • WordPress SMS Alert Order Notifications plugin <= 4.0.1 - Broken Access Control vulnerabilitySame generic ecosystem
  • phpMyFAQ 3.2.0-alpha before 4.1.9 and 4.2.0-alpha before 4.2.0-beta TOTP 2FA Bypass via SSO CallbacksSame generic ecosystem
  • phpMyFAQ before 4.1.9 and 4.2.0-alpha before 4.2.0-beta Missing Current-Password Step-Up on E-mail Change Enables Account TakeoverSame generic ecosystem
  • phpMyFAQ 4.2.0-alpha before 4.2.0-beta Missing Authorization via deleteGroup APISame generic ecosystem
  • phpMyFAQ 4.2.0-alpha.2 before 4.2.0-beta 2FA Brute-Force via remove-twofactor EndpointSame generic ecosystem

Record context

Vulnerability class
Vulnerability
EPSS
Not reported
CWE IDs
CWE-409
Source
CVE List V5
Source checked
Oct 17, 2026
References
1 linked source
Open source record