# CVE-2026-40612: jq: Stack overflow via unbounded recursion in jv_contains

> Attackers can cause a stack overflow and crash the application by providing deeply nested JSON structures to the jq library.

- **Severity:** Medium 5.4 (`CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 11 May 2026
- **Updated:** 11 May 2026
- **Also known as:** ALPINE-CVE-2026-40612, AZL-86381, BELL-CVE-2026-40612, DEBIAN-CVE-2026-40612, ECHO-1e5b-f6f3-755b, GHSA-r7m6-x9c7-h69j, UBUNTU-CVE-2026-40612

## What is CVE-2026-40612?

CVE-2026-40612 is a medium-severity denial of service vulnerability in jqlang jq, published on 11 May 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

jq is a command-line JSON processor. In 1.8.1 and earlier, jv_contains recurses into nested arrays/objects with no depth limit. With a sufficiently nested input structure (built programmatically with reduce, since the JSON parser caps at depth 10000), the C stack is exhausted.

Weakness: CWE-674 (Uncontrolled Recursion)

## Which versions are affected by CVE-2026-40612?

It affects 1 product.


Products: Jqlang Jq.

## How do I fix CVE-2026-40612?

Upgrade to a fixed version.

## Is CVE-2026-40612 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-40612 exists.

## Other vulnerabilities in jqlang jq

- [CVE-2026-32316](https://insights.sbomify.com/CVE-2026-32316/): jq: Integer overflow in jvp_string_append() allows Heap-based Buffer Overflow (high 8.2)
- [CVE-2024-53427](https://insights.sbomify.com/CVE-2024-53427/): Memory corruption in jq (high 8.1)
- [CVE-2025-48060](https://insights.sbomify.com/CVE-2025-48060/): AddressSanitizer: stack-buffer-overflow in jq_fuzz_execute (jv_string_vfmt) (high 7.7)
- [CVE-2023-49355](https://insights.sbomify.com/CVE-2023-49355/): Memory corruption in n/a (high 7.5)
- [CVE-2026-49839](https://insights.sbomify.com/CVE-2026-49839/): jq --rawfile invalid-state reuse after String too long causes heap-buffer-overflow (high 7.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-40612 and fix it if it is affected.

What it is: CVE-2026-40612 is a medium-severity denial of service vulnerability in jqlang jq, published on 11 May 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-40612 exists.

Affected product: jqlang jq. 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-2026-40612/ (Markdown: https://insights.sbomify.com/CVE-2026-40612/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-40612
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-40612
- OSV: https://osv.dev/vulnerability/CVE-2026-40612

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-40612/
Summaries are generated and may contain mistakes; the official description above is the record.