CVE-2026-103276: Ghost before 6.20.0 File Read via URL Encoding Bypass

Severity: medium (CVSS 5.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-10-01 · updated 2026-10-01
Weakness: CWE-173

Description

Ghost versions before 6.20.0 contain a file extension filtering bypass vulnerability that allows unauthenticated attackers to read theme templates and metadata. Attackers can use URL encoding to bypass extension validation and access sensitive theme files.

Affected products

TryGhost Ghost: before 6.20.0 — fixed in 6.20.0

How to fix

Upgrade to a fixed version: TryGhost Ghost 6.20.0. Check the vendor advisory for mitigations.

References

https://github.com/TryGhost/Ghost/security/advisories/GHSA-6v8p-3jx9-8chr
https://www.vulncheck.com/advisories/ghost-before-6.20.0-file-read-via-url-encoding-bypass

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