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GHSA-6439-2f28-8p8q
No affected components available
Description
Symfony's #[IsGranted('...')], #[IsSignatureValid], and #[IsCsrfTokenValid(...)] attributes allow you to define a methods: [...] argument to only enforce these checks for the listed HTTP methods and skip them otherwise. E.g. an attribute defining methods: ['GET'] would be ignored for a HEAD request.
On the other hand, Symfony's router (and HTTP semantics generally) serves HEAD requests using the GET handler. Therefore, a controller protected by e.g. #[IsGranted('ROLE_ADMIN', methods: ['GET'])] can be reached via HEAD with the authorization check silently skipped.
Even if the HEAD request won't get any response content, response headers leak (Content-Length, Location, custom headers). Also, the controller still executes and any side effects (DB writes, state changes) occur.
Resolution
When adding GET in the methods option of these attributes, Symfony now also include the HEAD method automatically.
The patch for this issue is available here for branch 7.4.
Credits
Symfony would like to thank Claude Mythos Preview (via Project Glasswing) for reporting the issue and Alexandre Daubois for fixing it.
The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker needs basic access or low-level privileges. No user interaction is needed for the attacker to exploit this vulnerability.
Exploitation attempts have been detected. Elevated vigilance and prompt remediation are advised.
The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.
We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.
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