json_repair: Circular JSON Schema $ref causes unbounded CPU DoS

Exploitation

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

CVSS

7.5 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS

No dated EPSS signal available.

As published by the source; long descriptions are shortened.

Circular JSON Schema $ref causes unbounded CPU DoS in jsonrepair Summary SchemaRepairer.resolveschema() in jsonrepair follows JSON Schema $ref pointers in an unbounded while loop without any cycle detection. An attacker who can supply a schema containing a self-referencing $ref (e.g., via the demo Flask API or any application that passes untrusted input to loads(..., schema=...)), can cause a worker process to spin indefinitely on CPU, resulting in a complete denial of service. No authentication is required against the public demo API. The vulnerability is confirmed reproducible at CVSS 7.5 (High). Details SchemaRepairer.resolveschema() at src/jsonrepair/schemarepair.py:184–190 resolves $ref chains using a plain while loop: resolveref() at src/jsonrepair/schemarepair.py:654–665 always resolves references relative to self.rootschema, which is initialised from the caller-supplied schema (src/jsonrepair/schemarepair.py:130). When the schema contains a circular reference such as:…

Published by the source

13 Jul 2026, 23:41 UTC

Last modified by the source

13 Jul 2026, 23:45 UTC

Source last checked

26 Oct 2026, 13:46 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-xf7x-x43h-rpqh

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-xf7x-x43h-rpqh

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# Patch Next advisory brief: GHSA-xf7x-x43h-rpqh

Advisory: json_repair: Circular JSON Schema `$ref` causes unbounded CPU DoS
IDs: GHSA-xf7x-x43h-rpqh
Record: https://patchnext.com/advisories/ghsa-xf7x-x43h-rpqh (revision 2, source checked 26 Oct 2026, 13:46 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: json-repair 0.60.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI json-repair: affected < 0.60.1; fixed in 0.60.1

## Suggested inspection (read-only)
- `python -m pip show json-repair`: prints the installed version. Run with the environment that serves production active.

## 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 json-repair.
- 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://osv.dev/vulnerability/GHSA-xf7x-x43h-rpqh (OSV record GHSA-xf7x-x43h-rpqh lists affected ranges: PyPI json-repair >=0 <0.60.1 (fixed))
- Verified: https://github.com/advisories/GHSA-xf7x-x43h-rpqh (GitHub-reviewed advisory GHSA-xf7x-x43h-rpqh lists affected ranges: PyPI json-repair >=0 <0.60.1)

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