Jawn: Uncontrolled nesting depth in JSON parser
Published Sep 23, 2026 · Updated Nov 3, 2026
Original summary
Normalized public record · Updated Nov 3, 2026
Jawn: Uncontrolled nesting depth in JSON parser
Publisher and source text is retained separately from QFinch interpretation.
QFinch assessment
The Jawn parser before 1.6.1 is vulnerable to a denial of service attack via untrusted input.
Potential 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.
Evidence: public source recordsAffected products
| Affected package, product or range | Fix status |
|---|---|
| Consult the referenced vendor advisory for affected versions. | Consult source advisory |
Matching a version is only one part of assessing exposure. QFinch has not assessed your environment on this public page.
Remediation
Apply the vendor-supported fixed release or mitigation, then verify the affected component is no longer reachable.
- Confirm the affected product and reachable code path exist in your environment.
- Apply the vendor-supported patch or mitigation from the primary advisory.
- Rescan the exact deployed revision and retain verification evidence.
Evidence coverage
- SSVC priority
- MEDIUM
- Confidence
- Not available
- Aliases
- None reported
Scores appear only when corresponding evidence exists. Missing data is never interpreted as zero risk.
Sources and record history
Record history
Published Sep 23, 2026 · Last refreshed Nov 3, 2026