Jawn: Quadratic parsing effort in AsyncParser
AsyncParser can be forced to perform O(n^2) work on the length of the input. When a single JSON token arrives across many small chunks, each absorb call rescans the incomplete token from the start.
Impact
Denial of service via CPU exhaustion when parsing untrusted JSON.
Preconditions:
- Application uses
AsyncParser - Attacker can send large tokens with control over chunk sizes.
Patches
Fixed in jawn-parser-1.7.0.
Workarounds
If you can't upgrade immediately:
- Use the synchronous
Parser. - Buffer incoming bytes into larger chunks before calling
absorb
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Java / Kotlin (Maven) | org.typelevel:jawn-parser_2.12 | < 1.7.0 | 1.7.0 |
| Java / Kotlin (Maven) | org.typelevel:jawn-parser_2.13 | < 1.7.0 | 1.7.0 |
| Java / Kotlin (Maven) | org.typelevel:jawn-parser_3 | < 1.7.0 | 1.7.0 |
References
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H- Weakness (CWE)
CWE-400, CWE-407- Platform
- Java / Kotlin (Maven)
- Package
org.typelevel:jawn-parser_2.12, org.typelevel:jawn-parser_2.13, org.typelevel:jawn-parser_3- Disclosed
- 23.09.2026
- Updated
- 11.10.2026 13:20
Sources and licenses
OSV / GitHub Advisory Database - GHSA-w4cm-gvhj-cgw6 - CC BY 4.0
Vulnerability history: org.typelevel:jawn-parser_3
All published vulnerabilities of this package (Java / Kotlin (Maven)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 3
- First → latest
- 01.2022 09.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- High 2
- Medium 1
Disclosures per year
- 2022: 1
- 2023: 0
- 2024: 0
- 2025: 0
- 2026: 2
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