CVE-2026-43894: Jqlang Jq

Medium severity, CVSS 5.5. EPSS: 0.2% chance of exploitation in the next 30 days.

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).

Affected products

• Jqlang Jq: up to and including 1.8.1

Published 2026-05-11. Last modified 2026-06-17.