CVE-2026-103276

Ghost before 6.20.0 File Read via URL Encoding Bypass

Published Oct 1, 2026 CVSS 4.0 · 6.9 Medium EPSS < 1% KEV · Not listed

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.

Analysis

Technical impact

Ghost versions prior to 6.20.0 allow unauthenticated attackers to read theme templates and metadata by bypassing file extension validation through URL encoding. This flaw enables the disclosure of potentially sensitive configuration files used by the CMS. The vulnerability is identified as a file read flaw (CWE‑173) and can be exploited remotely without authentication.

Affected Systems

All installations of Ghost older than 6.20.0 are susceptible. The affected product is the Ghost content management system (TryGhost:Ghost).

Risk and Exploitability

The CVSS score of 6.9 indicates moderate severity. No EPSS data is available, and the vulnerability is not listed in CISA’s KEV catalog, suggesting limited, if any, current exploitation in the wild. Attackers can exploit this remotely over the network by crafting a request containing URL‑encoded characters to trigger the bypass. Because no authentication is required, any external user can access the sensitive files if the CMS is exposed publicly.

Affected Products

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

TryGhost

Ghost

unaffected

Version	Status	Constraints
`0`	affected	< 6.20.0
`6.20.0`	unaffected	—

No data.

Vendor Product Versions

Ghost

Version	Status	Scheme	Platform
`[0,6.20.0)`	affected	semver	—
`6.20.0`	unaffected	semver	—

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

Upgrade Ghost to version 6.20.0 or later, which removes the URL‑encoding bypass and strengthens file extension checks.
If an upgrade is not immediately possible, enforce stricter file path restrictions on the web server or reverse proxy to disallow access to the theme directory and any files with disallowed extensions.
Limit exposure by ensuring the Ghost instance is behind authentication or a firewall that restricts external access to the admin and theme directories.
Monitor access logs for unusual file requests and investigate any unexpected file read attempts to detect potential exploitation attempts.

Generated by OpenCVE AI on October 1, 2026 at 14:43 UTC.

Tracking

Advisories

No advisories available

Metrics

Attack Vector Network

Attack Complexity Low

Privileges Required None

Attack Requirements None

User Interaction None

Vulnerable System Confidentiality Impact Low

Vulnerable System Integrity Impact None

Vulnerable System Availability Impact None

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact Low

Integrity Impact None

Availability Impact None

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploit prediction score: < 1% (0.226% probability within 30 days)

Exploitation none

Automatable yes

Technical Impact partial

References

Link	Providers
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

History

Oct 1, 2026 2:30 PM Scoring metrics updated View changes

Type	Values Removed	Values Added
Metrics		ssvc `{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}`

Oct 1, 2026 11:00 AM Description updated. Title updated. First appearance in the feed. Weaknesses updated. Affected versions updated. Affected vendors updated. Added references. Scoring metrics updated View changes

Type	Values Removed	Values Added
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.
Title		Ghost before 6.20.0 File Read via URL Encoding Bypass
First Time appeared		Ghost Ghost ghost
Weaknesses		CWE-173
CPEs		cpe:2.3:a:ghost:ghost::::::::
Vendors & Products		Ghost Ghost ghost
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
Metrics		cvssV3_1 `{'score': 5.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N'}` cvssV4_0 `{'score': 6.9, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N'}`