CVE-2026-72587
Instatic - Cache Poisoning via Unauthenticated Server Island Endpoint
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.
INFO
Published Date :
Aug. 10, 2026, 11:17 a.m.
Last Modified :
Aug. 28, 2026, 6:51 p.m.
Remotely Exploit :
No
Source :
309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c
Affected Products
The following products are affected by CVE-2026-72587
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | MEDIUM | 309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c | ||||
| CVSS 3.1 | MEDIUM | MITRE-CVE |
Solution
- Update the Instatic software.
- Ensure cache keys include full context.
- Remove or disable the affected endpoint.
- Implement proper input validation.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-72587.
| URL | Resource |
|---|---|
| https://github.com/CoreBunch/Instatic |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-72587 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-72587
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-72587 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-72587 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Aug. 10, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-72587', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-08-10T13:21:23.037495Z'} -
CVE Modified by 309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c
Aug. 10, 2026
Action Type Old Value New Value Changed Affected [{'vendor': 'CoreBunch', 'product': 'Instatic', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '0.0.14', 'versionType': 'semver'}]}] [{'vendor': 'CoreBunch', 'product': 'Instatic', 'versions': [{'status': 'affected', 'version': '0', 'versionType': 'semver', 'lessThanOrEqual': '0.0.14'}], 'defaultStatus': 'unknown'}] Changed 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. The originating-page URL supplied in u seeds the route template frame used for rendering, and the result is stored in a shared cache keyed only on nodeId, enabling an attacker to inject a crafted route that causes all subsequent visitors to receive malformed or attacker-controlled fragment content. 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. -
New CVE Received by 309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c
Aug. 10, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'CoreBunch', 'product': 'Instatic', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '0.0.14', 'versionType': 'semver'}]}] Added 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. The originating-page URL supplied in u seeds the route template frame used for rendering, and the result is stored in a shared cache keyed only on nodeId, enabling an attacker to inject a crafted route that causes all subsequent visitors to receive malformed or attacker-controlled fragment content. Added CVSS V3.1 AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N Added CWE CWE-444 Added Reference https://github.com/CoreBunch/Instatic