# CVE-2026-43894: jq: Wild stack write via signed-integer overflow in decNumber D2U() macro

> A signed-integer overflow in jq's decNumber library allows attackers to trigger a wild stack write, potentially leading to code execution or denial of service.

- **Severity:** Medium 6.2 (`CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 11 May 2026
- **Updated:** 11 May 2026
- **Also known as:** ALPINE-CVE-2026-43894, AZL-86372, BELL-CVE-2026-43894, DEBIAN-CVE-2026-43894, ECHO-be81-926b-05ab, GHSA-5v7p-2r57-2g4g, UBUNTU-CVE-2026-43894

## What is CVE-2026-43894?

CVE-2026-43894 is a medium-severity vulnerability in jqlang jq, published on 11 May 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

jq is a command-line JSON processor. In 1.8.1 and earlier, when decNumberFromString is given a number literal of INT_MAX-1 (2147483646) digits, the D2U() macro overflows during signed-int arithmetic. The wrapped negative value bypasses the heap-allocation size check, causes the function to use a 30-byte stack buffer, and then writes ≈715 million 16-bit units (≈1.4 GiB) at an offset 1.43 GiB below the stack frame. The written content is fully attacker-controlled (the parsed decimal digits, packed 3-per-unit).

Weakness: CWE-190 (Integer Overflow or Wraparound)

## Which versions are affected by CVE-2026-43894?

It affects 1 product.


Products: Jqlang Jq.

## How do I fix CVE-2026-43894?

Upgrade to a fixed version.

## Is CVE-2026-43894 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-43894 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-2026-43894 and fix it if it is affected.

What it is: CVE-2026-43894 is a medium-severity vulnerability in jqlang jq, published on 11 May 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-43894 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-2026-43894/ (Markdown: https://insights.sbomify.com/CVE-2026-43894/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-43894
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-43894
- OSV: https://osv.dev/vulnerability/CVE-2026-43894

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-43894/
Summaries are generated and may contain mistakes; the official description above is the record.