Vulnerability record
CVE-2026-125398
The short answer
CVE-2026-125398 affects CoreBunch Instatic and is rated high (CVSS 7.1). It is not in CISA's KEV catalog; EPSS puts the chance of exploitation in the next 30 days at 0.28%.
What it is
Instatic before 0.0.21 contains an authorization bypass vulnerability in handleRowAuthor that allows authenticated users to skip table-level access checks by loading rows with getDataRow() instead of loadRowForAccess(). Attackers holding content.edit.any but lacking data.system.tables.read can send PATCH requests to /admin/api/cms/data/rows/:id/author to read system-table rows and reassign their authors.
Weakness: CWE-862.
Severity
7.1 high
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Exploited (CISA KEV)
Not listed
CISA lists confirmed exploitation only
EPSS, next 30 days
0.28%
Higher than 20% of scored CVEs
How it can be exploited
- Attack vector
- Network
- Attack complexity
- Low
- Attack requirements
- None
- Privileges required
- Low
- User interaction
- None
- Confidentiality impact
- High
- Integrity impact
- Low
- Availability impact
- None
Affected products
Instatic. NVD's record lists the exact affected versions.
References
- github.com/CoreBunch/Instatic/blob/v0.0.20/server/handlers/cms/data/rows.ts#L378-L398
- github.com/CoreBunch/Instatic/commit/ff1e51eb59c860864fa24e8c3e2716b56314f3ad
- github.com/CoreBunch/Instatic/releases/tag/v0.0.21
- github.com/CoreBunch/Instatic/security/advisories/GHSA-m425-wmrc-4v4v
- www.vulncheck.com/advisories/instatic-before-0.0.21-authorization-bypass-via-row-author-reassignment-endpoint
Questions
Is CVE-2026-125398 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog as of 2026-11-11. FIRST's EPSS estimates a 0.28% chance of exploitation in the next 30 days.
How do I fix CVE-2026-125398?
Follow the vendor advisory in the references below. NVD lists the affected versions under its configurations.
From NVD, CISA KEV, FIRST EPSS and OSV.dev, checked . Status on NVD: Received. The description is NVD's text, quoted as published.
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