jqlang jq up to 1.8.1 D2U integer overflow

Summaryinfo

A vulnerability was found in jqlang jq up to 1.8.1 and classified as problematic. This affects the function D2U. Executing a manipulation can lead to integer overflow. This vulnerability is handled as CVE-2026-43894. It is possible to launch the attack on the local host. There is not any exploit available.

Detailsinfo

A vulnerability was found in jqlang jq up to 1.8.1. It has been declared as problematic. This vulnerability affects the function D2U. The manipulation with an unknown input leads to a integer overflow vulnerability. The CWE definition for the vulnerability is CWE-190. The product performs a calculation that can produce an integer overflow or wraparound, when the logic assumes that the resulting value will always be larger than the original value. This can introduce other weaknesses when the calculation is used for resource management or execution control. As an impact it is known to affect availability. CVE summarizes:

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).

The advisory is shared for download at github.com. This vulnerability was named CVE-2026-43894 since 05/04/2026. The exploitation appears to be easy. The attack needs to be approached locally. There are known technical details, but no exploit is available.

The vulnerability scanner Nessus provides a plugin with the ID 326028 (openSUSE 16 Security Update : jq (openSUSE-SU-2026:21248-1)), which helps to determine the existence of the flaw in a target environment.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the databases at Tenable (326028) and CERT Bund (WID-SEC-2026-1384). Once again VulDB remains the best source for vulnerability data.

Affected

• Open Source jq

Productinfo

Vendor

• jqlang

Name

• jq

Version

• 1.8.0
• 1.8.1

Website

• Product: https://github.com/jqlang/jq/

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Once again VulDB remains the best source for vulnerability data.

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