GHSA-cc4v-rvgp-2pf3
Jawn: Uncontrolled nesting depth in JSON parser
Packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| Maven | org.typelevel:jawn-parser_2.12 | < 1.7.0 | 1.7.0 |
| Maven | org.typelevel:jawn-parser_2.13 | < 1.7.0 | 1.7.0 |
| Maven | org.typelevel:jawn-parser_3 | < 1.7.0 | 1.7.0 |
Details
As written in the advisory (Markdown source, shown as plain text).
The Jawn parser before 1.6.1 is vulnerable to a denial of service attack via untrusted input.
### Impact
A remote attacker who can submit JSON to any jawn-backed parse method can exhaust JVM heap and trigger `java.lang.OutOfMemoryError`. This is treated by Scala as a fatal error and not typically handled by `scala.util.Try` or `cats.effect.IO`.
### Patches
Version `1.6.1` introduces a configurable nesting-depth limit (`Parser#maxDepth`, default `4096`). Inputs deeper than the limit fail with a recoverable `ParseException` instead of exhausting heap.
Users who require deeper nesting may override `maxDepth` on a `Parser` subclass.
### Workarounds
- Enforce an input size limit small enough that the resulting context stack cannot exhaust heap, (e.g. http4s `EntityLimiter`).
- Pre-scan untrusted input and reject documents whose maximum delimiter nesting exceeds a threshold before handing them to jawn.
References
External links from the advisory. They lead to third-party sites.
- https://github.com/typelevel/jawn/security/advisories/GHSA-cc4v-rvgp-2pf3
- https://github.com/typelevel/jawn/commit/191cb3a44e77f1afab439ee636bf66bdf3c54a04
- https://github.com/typelevel/jawn/commit/6219666641f9408498f85868f835e17bd8a72fed
- https://github.com/typelevel/jawn/commit/93ac93e9c992c11b4c03d5455d8551f9fb24da1b
- https://github.com/typelevel/jawn/commit/f6ace7e0db715de1a8c4618bed9378333a5c2214
- https://github.com/typelevel/jawn
- https://github.com/typelevel/jawn/releases/tag/v1.7.0