CVE-2026-59990Network attack vector

Application crash via unbounded JSON nesting

Published Sep 23, 2026 · Updated Sep 23, 2026

Resource exhaustion in Typelevel Jawn before 1.7.0 allows remote attackers to crash applications by submitting deeply nested JSON. Jawn parse methods accept arbitrary array and object nesting, growing parser contexts until they exhaust the JVM heap. Any application path that passes untrusted JSON to Jawn is exposed, and the resulting fatal OutOfMemoryError ordinarily escapes Scala error handlers.

CVSS severity7.5
High
EPSS probability0.62%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Get started

Summary

What happened

Resource exhaustion in Typelevel Jawn before 1.7.0 allows remote attackers to crash applications by submitting deeply nested JSON. Jawn parse methods accept arbitrary array and object nesting, growing parser contexts until they exhaust the JVM heap. Any application path that passes untrusted JSON to Jawn is exposed, and the resulting fatal OutOfMemoryError ordinarily escapes Scala error handlers.

The record

CVE
CVE-2026-59990
Published
Sep 23, 2026
Updated
Sep 23, 2026
Vendor
MVP Themes
Product
Jawn
Classifications
CWE-770, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 23, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 23, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 1.7.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

MVP Themes · Jawnversion=< 1.7.0

Published CVSS scores

7.5GitHub Security AdvisoryCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-770Allocation of Resources Without Limits or Throttling
T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Get started to see how Hinoki identifies affected software and validates exploitability in your environment.

Get started