Instatic - Cache Poisoning via Unauthenticated Server Island Endpoint (CVE-2026-72587) | HOL Guard CVE

Medium · CVSS 6.1CVE-2026-72587

Instatic - Cache Poisoning via Unauthenticated Server Island Endpoint

Answer in brief

CVE-2026-72587 records a Medium severity (CVSS 6.1) vulnerability in Instatic - Cache Poisoning via Unauthenticated Server Island Endpoint. The current sources do not mark it as known exploited. The current feed maps CoreBunch/Instatic (generic), CoreBunch/Instatic (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 Aug 10, 2026Updated Aug 28, 2026Source checked Sep 24, 2026First seen by HOL Aug 10, 2026Material review Aug 28, 2026

Upstream Advisory

Key facts

Risk: Medium · CVSS 6.1
Exploitation: Not marked as known exploited
Affected software: 2 mapped packages or products
Fix availability: Available

Why this deserves its current priority

CVSS is 6.1. 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 CoreBunch/Instatic (generic), CoreBunch/Instatic (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
CoreBunch/Instaticgeneric	>=0 <0.0.14	0.0.14
CoreBunch/Instaticgeneric	0	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for CoreBunch/Instatic, CoreBunch/Instatic.
Review the reported fix. Update CoreBunch/Instatic to 0.0.14 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Aug 10, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Aug 28, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Aug 10, 2026

Sources and claim methodology

GitHub security advisorygithub.com

Upstream source description

A cache poisoning vulnerability in CoreBunch/Instatic through 0.0.14 allows an unauthenticated remote attacker to poison the shared process-wide render cache by manipulating the u query parameter of the GET /_instatic/hole/<nodeId> server island endpoint.

Quoted source text, attributed separately from HOL analysis.