CVE-2026-72587 Instatic - Cache Poisoning via Unauthenticated Server Island Endpoint
An unauthenticated attacker can poison the shared render cache via the server island endpoint, potentially serving malicious content to other users.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-72587?
CVE-2026-72587 is a medium-severity vulnerability in CoreBunch Instatic, published on 10 Aug 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official 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.
Weakness: CWE-444
Which versions are affected by CVE-2026-72587?
How do I fix CVE-2026-72587?
No fix has been published for CVE-2026-72587 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-72587 being exploited?
There is no known exploitation of CVE-2026-72587 in the wild and no public exploit code.
Sources
Also known as GHSA-9p8f-ppfj-8gc5.