Summary
Pixelfed doesn't check OAuth Scopes in API routes, giving elevated permissions
When processing requests authorization was improperly and insufficiently checked, allowing attackers to access far more functionality than users intended, including to the administrative and moderator functionality of the Pixelfed server.
This vulnerability affects every version of Pixelfed between v0.10.4 and v0.11.9, inclusive. A proof of concept of this vulnerability exists.
Details
In vulnerable versions of Pixelfed (versions before 0.11.11), when the API checked the request for permissions to perform a certain behavior, it did not check that the OAuth Application/Client had granted access to those API endpoints, it only checked if the user was authenticated via an access token, and if the user was the owner of the resource or an admin on the instance.
This meant that an attacker could request an access token for "read" permissions to authenticate you with their application, but the access token that they obtained actually could be used for "write" or even administrative actions, and the user who granted access to their account had zero knowledge of this elevated access.
Proof of Concept
- Create an access token either via 2-legged OAuth flow for the
readscope, or create a Personal Access Tokens with thereadscope. - Using that Access Token, perform a request that would need a particular higher-privilege scope, for instance, following a user or performing an administrative request. (respectively requiring
followoradmin:readandadmin:writescopes in the patched versions) - Observe that despite your access token having
readpermissions, the follow or administrative request was successful.
e.g., Maybe an attacker collects an access token (which expires in 1 year) wants to do something really nasty to an admin, such as disabling federation on their target's pixelfed server. As long as that server has instance.enable_cc configured (defaults to true), then the attacker can use the read scoped access token and perform the following request:
POST /api/admin/config/update
Content-Type: application/json
Accept: application/json
Authorization: Bearer <access token with read scope>
{ "key": "federation.activitypub.enabled": "value": false }
And federation of that pixelfed server would be subsequently disabled, as if the administrator had disabled it.
Prior versions
Whilst this vulnerability is listed as >= 0.10.4, there is potential that versions before 0.10.4 are also vulnerable to this sort of security bypass, however, given that the code changed significantly between 0.10.3 and 0.10.4 we've been unable to easily assess if these heavily outdated versions are vulnerable or not to this exploit.
Sponsorship
The work involved in investigating and remediation of this security vulnerability was provided by Nivenly Foundation, for whom we are grateful for their support of the Fediverse and Pixelfed.
Impact
This vulnerability affects every local user of a Pixelfed server, and can potentially affect the servers' ability to federate.
Some user interaction is required to setup the conditions to be able to exercise the vulnerability, but the attacker could conduct this attack time-delayed manner, where user interaction is not actively required, since access tokens in Pixelfed have a 1-year lifetime before they expire, and users' often forget to revoke access tokens for applications that they are no longer using.
This also means that Access Tokens that may have been leaked from third-party OAuth Application's databases would be usable for a significant amount of time by potential attackers.
The application does not correctly enforce access controls, allowing a principal to access resources or operations beyond their granted permissions. Typical impact: unauthorized data access or execution of privileged operations.
CVE-2024-25108 has a CVSS score of 9.9 (Critical). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.11.11); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is CVE-2024-25108? CVE-2024-25108 is a critical-severity incorrect authorization vulnerability in pixelfed/pixelfed (composer), affecting versions >= 0.10.4, < 0.11.11. It is fixed in 0.11.11. The application does not correctly enforce access controls, allowing a principal to access resources or operations beyond their granted permissions.
- How severe is CVE-2024-25108? CVE-2024-25108 has a CVSS score of 9.9 (Critical). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of pixelfed/pixelfed are affected by CVE-2024-25108? pixelfed/pixelfed (composer) versions >= 0.10.4, < 0.11.11 is affected.
- Is there a fix for CVE-2024-25108? Yes. CVE-2024-25108 is fixed in 0.11.11. Upgrade to this version or later.
- Is CVE-2024-25108 exploitable, and should I be worried? Whether CVE-2024-25108 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2024-25108 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2024-25108? Upgrade
pixelfed/pixelfedto 0.11.11 or later.