Jawn: Uncontrolled nesting depth in JSON parser

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

7.5 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS

• CVE-2026-59990: 0.61% estimated exploitation activity in the next 30 days; percentile 49.51 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

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.

Published by the source

23 Sep 2026, 21:23 UTC

Last modified by the source

23 Sep 2026, 21:30 UTC

Source last checked

26 Oct 2026, 16:55 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-cc4v-rvgp-2pf3

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-cc4v-rvgp-2pf3

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# Patch Next advisory brief: CVE-2026-59990

Advisory: Jawn: Uncontrolled nesting depth in JSON parser
IDs: CVE-2026-59990, GHSA-cc4v-rvgp-2pf3
Record: https://patchnext.com/advisories/cve-2026-59990 (revision 2, source checked 26 Oct 2026, 16:55 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: org.typelevel:jawn-parser_2.13 1.7.0; org.typelevel:jawn-parser_2.12 1.7.0; org.typelevel:jawn-parser_3 1.7.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- Maven org.typelevel:jawn-parser_2.13: affected <= 1.6.0; fixed in 1.7.0
- Maven org.typelevel:jawn-parser_2.12: affected <= 1.6.0; fixed in 1.7.0
- Maven org.typelevel:jawn-parser_3: affected <= 1.6.0; fixed in 1.7.0

## Suggested inspection (read-only)
- Maven org.typelevel:jawn-parser_2.13: check the installed version with your package manager.
- Maven org.typelevel:jawn-parser_2.12: check the installed version with your package manager.
- Maven org.typelevel:jawn-parser_3: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on org.typelevel:jawn-parser_2.13, org.typelevel:jawn-parser_2.12, org.typelevel:jawn-parser_3.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-cc4v-rvgp-2pf3 (OSV record GHSA-cc4v-rvgp-2pf3 lists affected ranges: Maven org.typelevel:jawn-parser_2.12 >=0 =0 =0 <1.7.0 (fixed))
- Verified: https://github.com/advisories/GHSA-cc4v-rvgp-2pf3 (GitHub-reviewed advisory GHSA-cc4v-rvgp-2pf3 lists affected ranges: Maven org.typelevel:jawn-parser_2.12 >=0 =0 =0 <=1.6.0)

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