# CVE-2026-61814: Typelevel Jawn AsyncParser quadratic parsing effort denial of service

Source: https://junglewise.ai/threats/cve-2026-61814-typelevel-jawn-asyncparser-quadratic-parsing-effort-denial-of  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-23. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2026-61814 · Severity: high · CVSS 7.5 · Published 2026-09-23

Jawn is a widely-used JSON parsing library. Its AsyncParser component suffers from an algorithmic flaw that causes it to perform quadratic (O(n²)) work when processing large JSON tokens split across many small network chunks. An attacker who can send malicious JSON input with controlled chunk sizes can exhaust CPU resources, causing a denial-of-service condition in any application using AsyncParser for untrusted data.

Technologies: [org.typelevel:jawn-parser_2.12 (Maven)](https://junglewise.ai/threats/technologies/org-typelevel-jawn-parser-2-12), [org.typelevel:jawn-parser_2.13 (Maven)](https://junglewise.ai/threats/technologies/org-typelevel-jawn-parser-2-13), [org.typelevel:jawn-parser_3 (Maven)](https://junglewise.ai/threats/technologies/org-typelevel-jawn-parser-3). Vendors: [Maven](https://junglewise.ai/threats/vendors/maven).

## Quick answers

**Is CVE-2026-61814 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-61814 being exploited in the wild.

**How severe is CVE-2026-61814?** High severity, with a CVSS score of 7.5, published 23 September 2026.

**Which products and versions are affected?** org.typelevel:jawn-parser_2.12 (Maven) <= 1.6.0, ECOSYSTEM:introduced=0,fixed=1.7.0; org.typelevel:jawn-parser_2.13 (Maven) <= 1.6.0, ECOSYSTEM:introduced=0,fixed=1.7.0; org.typelevel:jawn-parser_3 (Maven) <= 1.6.0, ECOSYSTEM:introduced=0,fixed=1.7.0; Typelevel Jawn ≤ 1.6.0.

**Is there a fix for CVE-2026-61814?** Yes. org.typelevel:jawn-parser_2.12 (Maven): upgrade to 1.7.0 or later; org.typelevel:jawn-parser_2.13 (Maven): upgrade to 1.7.0 or later; org.typelevel:jawn-parser_3 (Maven): upgrade to 1.7.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-61814 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-61814?** Check whether you run org.typelevel:jawn-parser_2.12 (Maven), org.typelevel:jawn-parser_2.13 (Maven), org.typelevel:jawn-parser_3 (Maven) or one of the others listed at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- org.typelevel:jawn-parser_2.12 (Maven): upgrade to 1.7.0 or later

  ```sh
  # set org.typelevel:jawn-parser_2.12 to 1.7.0 in your pom.xml or build.gradle
  ```

- org.typelevel:jawn-parser_2.13 (Maven): upgrade to 1.7.0 or later

  ```sh
  # set org.typelevel:jawn-parser_2.13 to 1.7.0 in your pom.xml or build.gradle
  ```

- org.typelevel:jawn-parser_3 (Maven): upgrade to 1.7.0 or later

  ```sh
  # set org.typelevel:jawn-parser_3 to 1.7.0 in your pom.xml or build.gradle
  ```


## Technical details

The vulnerability is an algorithmic complexity flaw (CWE-407) in the AsyncParser component of Jawn. When a single JSON token arrives fragmented across many small network chunks, each call to the `absorb()` method rescans the incomplete token from the beginning rather than continuing from where the previous chunk left off, resulting in quadratic time complexity O(n²) with respect to token length. An attacker with the ability to control network transmission chunk sizes—or any network-accessible application parsing untrusted JSON—can trigger this behavior. The attack requires no authentication or user interaction; an unauthenticated remote attacker can send crafted JSON payloads to exhaust CPU and cause denial of service. The vulnerability was fixed in jawn-parser version 1.7.0.

## Affected products

- Typelevel Jawn ≤ 1.6.0

## Identifiers

- CVE-2026-61814
- GHSA-w4cm-gvhj-cgw6

## Timeline

- 2026-06-24: disclosed
- 2026-06-24: patched: Fixed in version 1.7.0
- 2026-09-23: advisory

## References

- [https://api.github.com/users/rossabaker](https://api.github.com/users/rossabaker)

## Related threats

- [Jawn JSON parser denial of service via uncontrolled nesting depth](https://junglewise.ai/threats/cve-2026-59990-jawn-json-parser-denial-of-service-via-uncontrolled-nesting-depth)
- [Hash collision in typelevel jawn](https://junglewise.ai/threats/cve-2022-21653-hash-collision-in-typelevel-jawn)