# CVE-2026-67217: cJSON JSON Patch Non-Atomic Application Destroys Data Before Validation

> Attackers can destroy data in JSON documents by supplying malformed patches that fail validation after mutation, affecting applications using cJSON.

- **Severity:** Medium 6.9 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 29 Jul 2026
- **Updated:** 29 Jul 2026
- **Also known as:** DEBIAN-CVE-2026-67217, GHSA-pr46-97qf-f32c, UBUNTU-CVE-2026-67217

## What is CVE-2026-67217?

CVE-2026-67217 is a medium-severity vulnerability in DaveGamble cJSON, published on 29 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

cJSON through 1.7.19 applies RFC 6902 JSON Patch operations non-atomically in apply_patch() in cJSON_Utils.c. For a replace operation that is missing its value member, or a move operation whose destination path cannot be resolved, the existing target member is detached and deleted before the operation is fully validated, so the target document is mutated while cJSONUtils_ApplyPatches() or cJSONUtils_ApplyPatchesCaseSensitive() returns a failure status. An attacker who can supply the patch document can destroy addressable members of the target document even though the API reports that the patch failed, defeating the all-or-nothing behavior callers rely on to reject bad patches.

Weakness: CWE-696 (Incorrect Behavior Order)

## Which versions are affected by CVE-2026-67217?

It affects 1 product.


Products: Davegamble Cjson.

## How do I fix CVE-2026-67217?

No fix has been published for CVE-2026-67217 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-67217 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-67217 exists.

## Other vulnerabilities in DaveGamble cJSON

- [CVE-2025-57052](https://insights.sbomify.com/CVE-2025-57052/): Memory corruption in n/a (critical 9.8)
- [CVE-2019-11834](https://insights.sbomify.com/CVE-2019-11834/): Memory corruption in n/a (critical 9.8)
- [CVE-2019-11835](https://insights.sbomify.com/CVE-2019-11835/): Memory corruption in n/a (critical 9.8)
- [CVE-2016-10749](https://insights.sbomify.com/CVE-2016-10749/): Memory corruption in n/a (critical 9.8)
- [CVE-2018-1000217](https://insights.sbomify.com/CVE-2018-1000217/): Use after free in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-67217 and fix it if it is affected.

What it is: CVE-2026-67217 is a medium-severity vulnerability in DaveGamble cJSON, published on 29 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-67217 exists.

Affected product: DaveGamble cJSON. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-67217/ (Markdown: https://insights.sbomify.com/CVE-2026-67217/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-67217
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-67217
- OSV: https://osv.dev/vulnerability/CVE-2026-67217

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-67217/
Summaries are generated and may contain mistakes; the official description above is the record.