Vulnerability in Corebunch Instatic

CVE-2026-72587

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.

Vulnerability class: HTTP Request Smuggling

Published · last modified .

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.002 (8.4th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 8th percentile — 8.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-72587: held from 0.002 to 0.002.

EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: 0.000

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-72587?
CVE-2026-72587 is a medium-severity vulnerability in Corebunch Instatic, classified under Inconsistent Interpretation of HTTP Requests (HTTP Request/Response Smuggling). CVSS score: 6.1/10. Published 2026-08-10.
How severe is CVE-2026-72587?
Medium severity. CVSS v3 base score is 6.1 out of 10.