Headline
CVE-2022-39288: Deny of service via malicious Content-Type
fastify is a fast and low overhead web framework, for Node.js. Affected versions of fastify are subject to a denial of service via malicious use of the Content-Type header. An attacker can send an invalid Content-Type header that can cause the application to crash. This issue has been addressed in commit fbb07e8d and will be included in release version 4.8.1. Users are advised to upgrade. Users unable to upgrade may manually filter out http content with malicious Content-Type headers.
Impact
An attacker can send an invalid Content-Type header that can cause the application to crash, leading to a possible Denial of Service attack. Only the v4.x line is affected.
(This was updated: upon a close inspection, v3.x is not affected after all).
Patches
Yes, update to >v4.8.0.
Workarounds
You can reject the malicious content types before the body parser enters in action.
const badNames = Object.getOwnPropertyNames({}.__proto__) fastify.addHook('onRequest’, async (req, reply) => { for (const badName of badNames) { if (req.headers[‘content-type’].indexOf(badName) > -1) { reply.code(415) throw new Error(‘Content type not supported’) } } })
References
See the HackerOne report #1715536
For more information
Fastify security policy
Related news
### Impact An attacker can send an invalid `Content-Type` header that can cause the application to crash, leading to a possible Denial of Service attack. Only the v4.x line is affected. (This was updated: upon a close inspection, v3.x is not affected after all). ### Patches Yes, update to `> v4.8.0`. ### Workarounds You can reject the malicious content types before the body parser enters in action. ```js const badNames = Object.getOwnPropertyNames({}.__proto__) fastify.addHook('onRequest', async (req, reply) => { for (const badName of badNames) { if (req.headers['content-type'].indexOf(badName) > -1) { reply.code(415) throw new Error('Content type not supported') } } }) ``` ### References See the HackerOne report [#1715536](https://hackerone.com/bugs?report_id=1715536&subject=fastify) ### For more information [Fastify security policy](https://github.com/fastify/fastify/security/policy)