CVE-2026-43894
jq: Wild stack write via signed-integer overflow in decNumber D2U() macro
CVSS Score
6.2
EPSS Score
0.0%
EPSS Percentile
0th
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).
| CWE | CWE-190 |
| Vendor | jqlang |
| Product | jq |
| Published | May 11, 2026 |
| Last Updated | May 11, 2026 |
Stay Ahead of the Next One
Get instant alerts for jqlang jq
Be the first to know when new medium vulnerabilities affecting jqlang jq are published — delivered to Slack, Telegram or Discord.
Get Free Alerts →
Free · No credit card · 60 sec setup
CVSS v3 Breakdown
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Attack Vector
Local
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High
Affected Versions
jqlang / jq
<= 1.8.1