Impact

Specifically crafted malicious themes can execute arbitrary code on the server running Ghost.

Vulnerable Versions

This vulnerability is present in Ghost v0.7.2 to v6.19.0.

Patches

v6.19.1 contains a fix for this issue.

Workarounds

Ghost generally recommends users refrain from installing untrusted themes. If a malicious theme has already been installed, it is recommended to uninstall the theme and then inspect it to understand its impact, which will be attack-specific.

References Ghost thanks Cristian-Alexandru Staicu at Endor Labs for disclosing this vulnerability responsibly.

For more information

If there are any questions or comments about this advisory, email Ghost at security@ghost.org.

DISPUTED An arbitrary file upload vulnerability in the file upload module of Ghost v4.39.0 allows attackers to execute arbitrary code via a crafted SVG file. NOTE: Vendor states that as outlined in Ghost's security documentation, upload of SVGs is only possible by trusted authenticated users. The uploading of SVG files to Ghost does not represent a remote code execution vulnerability. SVGs are not executable on the server, and may only execute javascript in a client's browser - this is expected and intentional functionality.

DISPUTED An arbitrary file upload vulnerability in the file upload module of Ghost CMS v4.42.0 allows attackers to execute arbitrary code via a crafted file. NOTE: Vendor states as detailed in Ghost's security documentation, files can only be uploaded and published by trusted users, this is intentional.

A code execution vulnerability exists in the Statement Bindings functionality of Ghost Foundation node-sqlite3 5.1.1. A specially-crafted Javascript file can lead to arbitrary code execution. An attacker can provide malicious input to trigger this vulnerability.

Impact

When Ghost is behind a shared caching layer that results in cached content being shared between different visitors (e.g., Fastly, Cloudflare, nginx proxycache, and others), an unauthenticated user could send an x-ghost-preview header that altered the rendered frontend response. In affected cache configurations, that response could be stored and served to subsequent visitors requesting the same page, allowing cache poisoning of request-specific preview output.

When running Ghost's frontend and admin panel on the same domain this could be used to take over staff user accounts. When running these on different domains staff accounts have no exposure.

Vulnerable versions

This vulnerability is present in Ghost from v4.0 up to v6.36.0.

Patches

v6.37.0 contains a fix for this issue.

How to update

For self-hosters using Docker, find Docker's official Ghost image here. Updating a Docker-based Ghost instance is documented here.

If your Ghost is a Ghost-CLI install see our documentation on updating it to the latest version here.

If you suspect a credential compromise, use the “Reset all authentication” dialogue under Settings / Danger Zone. This is available starting with Ghost v6.41.0.

Workarounds

At the caching layer, bypass the cache for x-ghost-preview requests.

References

Ghost thanks CryptoCat for disclosing this vulnerability responsibly.

For more information

If you have any questions or comments about this advisory, email us at security@ghost.org.

An authentication bypass vulnerability exists in the newsletter subscription functionality of Ghost Foundation Ghost 5.9.4. A specially-crafted HTTP request can lead to increased privileges. An attacker can send an HTTP request to trigger this vulnerability.

Impact

A SQL injection vulnerability existed in Ghost's Content API that allowed unauthenticated attackers to read arbitrary data from the database.

Vulnerable Versions

This vulnerability is present in Ghost v3.24.0 to v6.19.0.

Patches

v6.19.1 contains a fix for this issue.

Workarounds

There is no application-level workaround. The Content API key is public by design, so restricting key access does not mitigate this vulnerability.

As a temporary mitigation, a reverse proxy or WAF rule can be used to block Content API requests containing slug%3A%5B or slug:[ in the query string filter parameter. Note that this may break legitimate slug filter functionality.

References

We thank Nicholas Carlini using Claude, Anthropic for disclosing this vulnerability responsibly.

For more information If you have any questions or comments about this advisory, email us at security@ghost.org.

Ghost through 5.85.1 allows remote attackers to bypass an authentication rate-limit protection mechanism by using many X-Forwarded-For headers with different values. NOTE: the vendor's position is that Ghost should be installed with a reverse proxy that allows only trusted X-Forwarded-For headers.

Ghost through 5.76.0 allows stored XSS, and resultant privilege escalation in which a contributor can take over any account, via an SVG profile picture that contains JavaScript code to interact with the API on localhost TCP port 3001. NOTE: The discoverer reports that "The vendor does not view this as a valid vector."

An insecure default vulnerability exists in the Post Creation functionality of Ghost Foundation Ghost 5.9.4. Default installations of Ghost allow non-administrator users to inject arbitrary Javascript in posts, which allow privilege escalation to administrator via XSS. To trigger this vulnerability, an attacker can send an HTTP request to inject Javascript in a post to trick an administrator into visiting the post.A stored XSS vulnerability exists in the codeinjectionfoot for a post.

An insecure default vulnerability exists in the Post Creation functionality of Ghost Foundation Ghost 5.9.4. Default installations of Ghost allow non-administrator users to inject arbitrary Javascript in posts, which allow privilege escalation to administrator via XSS. To trigger this vulnerability, an attacker can send an HTTP request to inject Javascript in a post to trick an administrator into visiting the post.A stored XSS vulnerability exists in the codeinjectionhead for a post.

An insecure default vulnerability exists in the Post Creation functionality of Ghost Foundation Ghost 5.9.4. Default installations of Ghost allow non-administrator users to inject arbitrary Javascript in posts, which allow privilege escalation to administrator via XSS. To trigger this vulnerability, an attacker can send an HTTP request to inject Javascript in a post to trick an administrator into visiting the post.A stored XSS vulnerability exists in the facebook field for a user.

An insecure default vulnerability exists in the Post Creation functionality of Ghost Foundation Ghost 5.9.4. Default installations of Ghost allow non-administrator users to inject arbitrary Javascript in posts, which allow privilege escalation to administrator via XSS. To trigger this vulnerability, an attacker can send an HTTP request to inject Javascript in a post to trick an administrator into visiting the post.A stored XSS vulnerability exists in the twitter field for a user.

Ghost before 5.82.0 allows CSV Injection during a member CSV export.

Impact An attacker was able to craft a malicious link that, when accessed by an authenticated staff user or member, would execute JavaScript with the victim's permissions, potentially leading to account takeover.

Vulnerable versions This vulnerability is present in Ghost versions: - v5.43.0 to v5.120.4 - v6.0.0 to v6.14.0

As well as in Portal versions: - v2.29.1 to v2.51.4 - v2.52.0 to v2.57.0

Patches Ghost automatically loads the latest patch of the members Portal component via CDN. Therefore: - For Ghost 5.x users, upgrading to v5.121.0 or later fixes the vulnerability (loads Portal v2.51.5, which contains the patch) - For Ghost 6.x users, upgrading to v6.15.0 or later fixes the vulnerability (loads Portal v2.57.1, which contains the patch)

For Ghost installations using a customised or self-hosted version of Portal, it will be necessary to manually rebuild from or update to the latest patch version.

References Ghost thanks Younes Belalia for discovering and disclosing this vulnerability responsibly.

For more information If users have any questions or comments about this advisory, email Ghost at security@ghost.org.

Impact

Incomplete CSRF protections around /session/verify made it possible to use OTCs in login sessions different from the requesting session. In some scenarios this might have made it easier for phishers to take over a Ghost site.

Vulnerable versions

This vulnerability is present in Ghost from v5.101.6 up to v6.19.2.

Patches

v6.19.3 contains a fix for this issue.

How to update

For self-hosters using Docker, find Docker's official Ghost image here. Updating a Docker-based Ghost instance is documented here.

If a project's Ghost is a Ghost-CLI install see the documentation on updating it to the latest version here.

For more information

If there are any questions or comments about this advisory, send an email to security@ghost.org.

Ghost versions from 2.10.0 before 6.63.0 contain a staff enumeration vulnerability in the content API that allows unauthenticated attackers to leak user data. Attackers can observe discrepancies in API metadata responses to enumerate staff members and extract sensitive information without authentication.

Ghost versions before 6.62.0 contain an authentication bypass vulnerability that allows suspended staff users to reactivate their accounts through self-service password reset. Attackers with suspended staff credentials can perform password reset operations to regain active account access and restore their original privileges.

Ghost versions from 4.0.0 before 6.63.0 contain a content API vulnerability that allows unauthenticated visitors to access gated post content. Attackers can bypass content restrictions by directly querying the content API to retrieve restricted posts without authentication.

Ghost versions from 0.5.3 through versions prior to 6.50.0 fail to sanitize the data placed in the JSON-LD HTML tag emitted by the {{ghosthead}} helper. An authenticated user with limited privileges can inject unescaped content that is rendered as script in the published page, potentially leading to compromise of a staff user's admin session when that user views the affected page.

Ghost versions from 2.5.0 before 6.34.0 contain an untrusted script execution vulnerability in the oEmbed preview feature that fails to sandbox externally hosted scripts. Attackers can craft malicious oEmbed content to execute scripts in the context of a staff user's admin session, potentially compromising administrative access.

Ghost versions 6.20.0 before 6.57.1 contain a session handling vulnerability that allows authenticated staff users to log in as any other staff user with only the password, bypassing two-factor authentication. Attackers with valid staff credentials can exploit improper session management to impersonate other staff members and gain unauthorized access to administrative functions.

Ghost from 6.10.3 before 6.64.0 contains a remote code execution vulnerability that allows authenticated administrators to run code by abusing theme translation file loading. Attackers with administrator access can upload a crafted theme containing malicious translation files to execute arbitrary code on the Ghost server.

Ghost versions from 2.21.0 before 6.56.0 contain a privilege escalation vulnerability in the notifications system that allows low-privilege staff users to escalate to higher-privilege staff roles. Attackers with low-privilege staff access can exploit the notifications system to gain elevated privileges without proper authorization checks.

Ghost versions 5.8.0 before 6.34.0 contain an input validation vulnerability in the admin iframe that allows attackers to take over staff user accounts. Attackers with content publishing privileges can craft malicious pages that, when visited by active staff users, enable account takeover through improper input validation.

Ghost from 5.94.0 before 6.64.0 contains a stored cross-site scripting vulnerability that allows staff users, including Contributors, to host arbitrary HTML by abusing bookmark card image fetching. Attackers can create bookmark cards that store non-image files from external websites as icons or thumbnails to compromise other staff users' admin sessions.

Ghost from 6.22.1 before 6.64.0 contains a stored cross-site scripting vulnerability that allows staff users to host scripts by uploading files served with extension-derived content types on the default local storage adapter. Attackers can upload script-bearing files to the site's domain to compromise other staff users' admin sessions.

Impact A vulnerability in Ghost's handling of Staff Token authentication allowed certain endpoints to be accessed that were only intended to be accessible via Staff Session authentication. External systems that have been authenticated via Staff Tokens for Admin/Owner-role users would have had access to these endpoints.

Vulnerable versions This vulnerability is present in Ghost v5.121.0 to v5.130.5 to and Ghost v6.0.0 to v6.10.3.

Patches v5.130.6 and v6.11.0 contain a fix for this issue.

References Ghost thanks Sho Odagiri of GMO Cybersecurity by Ierae, Inc. for discovering and disclosing this vulnerability responsibly.

For more information If there are any questions or comments about this advisory, email Ghost at security@ghost.org.

Impact A vulnerability in Ghost's 2FA mechanism allows staff users to skip email 2FA.

Vulnerable versions This vulnerability is present in Ghost v5.105.0 to v5.130.5 to and Ghost v6.0.0 to v6.10.3.

Patches v5.130.6 and v6.11.0 contain a fix for this issue.

References Ghost thanks Sho Odagiri of GMO Cybersecurity by Ierae, Inc. for discovering and disclosing this vulnerability responsibly.

For more information If there are any questions or comments about this advisory, email Ghost at security@ghost.org.

Server-side request forgery (SSRF) vulnerability in Ghost CMS < 3.10.0 allows an attacker to scan local or external network or otherwise interact with internal systems.