Micronaut vulnerable to DoS via crafted form-urlencoded body binding with descending array indices

Exploitation

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

CVSS 4.0

8.2 · CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N · score source

EPSS

• CVE-2026-33013: 0.60% estimated exploitation activity in the next 30 days; percentile 49.02 (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.

In JsonBeanPropertyBinder::expandArrayToThreshold in io.micronaut:micronaut-json-core before Micronaut 4 4.10.16 and in Micronaut 3 before 3.10.5 does not correctly handle descending array index order during form-urlencoded body binding, which allows remote attackers to cause a denial of service (non-terminating loop, CPU exhaustion, and OutOfMemoryError) via crafted indexed form parameters (e.g., authors[1].name followed by authors[0].name). Example With such an application Sending curl -v -X POST 'http://127.0.0.1:8080/submit' -H 'Content-Type: application/x-www-form-urlencoded' --data-urlencode 'authors[1].name=RobertGalbraith' --data-urlencode 'authors[0].name=JKRowling' causes sustained CPU usage and unbounded memory growth (eventually OutOfMemoryError). Patches For Micronaut 4, the problem has been patched in micronaut-core, dependencies with group id io.micronaut, since 4.10.16. For Micronaut 3, the problem has been patched since 3.10.5 Users upgrade to the latest version of…

Published by the source

17 Mar 2026, 16:59 UTC

Last modified by the source

31 Mar 2026, 18:45 UTC

Source last checked

26 Oct 2026, 16:45 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-43w5-mmxv-cpvh

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# Patch Next advisory brief: CVE-2026-33013

Advisory: Micronaut vulnerable to DoS via crafted form-urlencoded body binding with descending array indices
IDs: CVE-2026-33013, GHSA-43w5-mmxv-cpvh
Record: https://patchnext.com/advisories/cve-2026-33013 (revision 1, source checked 26 Oct 2026, 16:45 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.2)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: io.micronaut:micronaut-json-core 4.10.16, 3.10.5, 3.8.13. A vendor fix does not mean a deployment is fixed.

## Affected components
- Maven io.micronaut:micronaut-json-core: affected >= 4.0.0-M1, < 4.10.16; >= 3.9.0, < 3.10.5; < 3.8.13; fixed in 3.8.13, 3.10.5, 4.10.16

## Suggested inspection (read-only)
- Maven io.micronaut:micronaut-json-core: 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 io.micronaut:micronaut-json-core.
- 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://github.com/advisories/GHSA-43w5-mmxv-cpvh (GitHub-reviewed advisory GHSA-43w5-mmxv-cpvh lists affected ranges: Maven io.micronaut:micronaut-json-core >=4.0.0-M1 =3.9.0 =0 <3.8.13)

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