How severe is CVE-2022-21653?

CVE-2022-21653 has a CVSS score of 5.9/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2022-21653?

CVE-2022-21653 affects the following packages: org.typelevel:jawn-parser_0.25 (Maven), org.typelevel:jawn-parserg (Maven), org.typelevel:jawn-parser_0.27 (Maven), org.typelevel:jawn-parser_2.10 (Maven), org.typelevel:jawn-parser_2.11 (Maven), org.typelevel:jawn-parser_2.12 (Maven), org.typelevel:jawn-parser_2.13 (Maven), org.typelevel:jawn-parser_2.13.0-M5 (Maven), and 10 more. Ecosystems affected: Maven.

How do I fix CVE-2022-21653?

No patched version of org.typelevel:jawn-parser_0.25 has shipped for CVE-2022-21653 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.

How do I detect CVE-2022-21653 in my Maven dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.typelevel:jawn-parser_0.25, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2022-21653 if there is no patch (or I can't update yet)?

Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Is CVE-2022-21653 actively exploited in the wild?

Yes. There are 1 known exploit references for CVE-2022-21653, including 1 in-the-wild exploitation observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2022-21653?

CVE-2022-21653 has an EPSS (Exploit Prediction Scoring System) score of 0.8%, placing it in the 55th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2022-21653?

CVE-2022-21653 is classified as Uncontrolled Resource Consumption (CWE-400), CWE-326 (CWE-326). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2022-21653 published, and has it been updated?

CVE-2022-21653 was published on January 5, 2022 and was last updated on August 12, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

☕

☕ Maven

Not in CISA KEV

MEDIUM severity

CVE-2022-21653 — jawn-parser_0.25

MEDIUMFix: typelevel/jawn#390

CVE-2022-21653 is a medium-severity (CVSS 5.9) Uncontrolled Resource Consumption vulnerability in org.typelevel:jawn-parser_0.25. 1 public exploit reference exists, so weaponization risk is real. A fix is available for org.typelevel:jawn-parser_0.25 — see the affected versions and patch details below.

Hash collision in typelevel jawn

Also known asGHSA-vc89-hccf-rq55

Published

Jan 5, 2022

Updated

Aug 12, 2026

Affected

18 pkgs

Patched

3 / 18

Exploits

1 known

Exploitation data as of Oct 12, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

Proof-of-concept exploit code exists

CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.

Exploitation and automatability from CISA’s SSVC triage for CVE-2022-21653.

EPSS Exploitation Probability

via FIRST.org ↗

0.8%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs55th percentile — riskier than 55% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2022-21653 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 385,987 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

18 pkgs affected

☕org.typelevel:jawn-parser_0.25☕org.typelevel:jawn-parserg☕org.typelevel:jawn-parser_0.27☕org.typelevel:jawn-parser_2.10☕org.typelevel:jawn-parser_2.11☕org.typelevel:jawn-parser_2.12☕org.typelevel:jawn-parser_2.13☕org.typelevel:jawn-parser_2.13.0-M5+10 more

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.

Description

Impact

Extenders of the org.typelevel.jawn.SimpleFacade and org.typelevel.jawn.MutableFacade who don't override objectContext() are vulnerable to a hash collision attack. Most applications do not implement these traits directly, but inherit from a library:

Affected implementations include:

org.http4s :: http4s-play-json
org.typelevel :: jawn-ast (< 0.8.0)
org.typelevel :: jawn-play (discontinued)
org.typelevel :: jawn-rojoma (discontinued)
org.typelevel :: jawn-spray (discontinued)

Unaffected implementations include:

io.argonaut :: argonaut-jawn
io.circe :: circe-parser
org.typelevel :: jawn-ast (>= 0.8.0)
org.typelevel :: jawn-json4s (discontinued)
org.typelevel :: jawn-argonaut (discontinued)

Patches

jawn-parser-1.3.2 fixes the issue.

Workarounds

Override objectContext() to use a collision-safe collection. See the patch for an example in both SimpleFacade and MutableFacade.

References

https://github.com/typelevel/jawn/pull/390

Credits

@kag0, for the report and the patch

For more information

If you have any questions or comments about this advisory:

Open an issue in typelevel/jawn
E-mail a maintainer:
- @rossabaker

Affected Packages

18 total 3 fixed

Ecosystem	Package	Vulnerable range	Fix
☕Maven	`org.typelevel:jawn-parser_0.25`	all versions	No fix
☕Maven	`org.typelevel:jawn-parserg`	all versions	No fix
☕Maven	`org.typelevel:jawn-parser_0.27`	all versions	No fix
☕Maven	`org.typelevel:jawn-parser_2.10`	all versions	No fix
☕Maven	`org.typelevel:jawn-parser_2.11`	all versions	No fix
☕Maven	`org.typelevel:jawn-parser_2.12`	all versions	1.3.2`org.typelevel:jawn-parser_2.12:1.3.2`

Affected Products

1 product · 1 configurations

Application

jawntypelevel

< 1.3.2

range

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

Jawn is an open source JSON parser. Extenders of the `org.typelevel.jawn…

github.comNVDJan 2022

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.typelevel:jawn-parser_0.25, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
No patched version of org.typelevel:jawn-parser_0.25 has shipped for CVE-2022-21653 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Workarounds
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Frequently Asked Questions

### Impact Extenders of the `org.typelevel.jawn.SimpleFacade` and `org.typelevel.jawn.MutableFacade` who don't override `objectContext()` are vulnerable to a hash collision attack. Most applications do not implement these traits directly, but inherit from a library: Affected implementations include: * `org.http4s` :: `http4s-play-json` * `org.typelevel :: jawn-ast` (< 0.8.0) * `org.typelevel :: jawn-play` (discontinued) * `org.typelevel :: jawn-rojoma` (discontinued) * `org.typelevel :: jawn-spray` (discontinued) Unaffected implementations include: * `io.argonaut :: argonaut-jawn` * `io.ci