CVE-2026-39956

6.1 MEDIUM 0.2% exploit odds Fix listed Memory safety Library

What it is

jq is a command-line JSON processor. Prior to version 1.8.2, the _strindices builtin in jq's src/builtin.c passes its arguments directly to jv_string_indexes() without verifying they are strings, and jv_string_indexes() in src/jv.c relies solely on assert() checks that are stripped in release builds compiled with -DNDEBUG. This allows an attacker to crash jq trivially with input like _strindices(0), and by crafting a numeric value whose IEEE-754 bit pattern maps to a chosen pointer, achieve a controlled pointer dereference and limited memory read/probe primitive. Any deployment that evaluates untrusted jq filters against a release build is vulnerable. This issue has been patched in commit fdf8ef0f0810e3d365cdd5160de43db46f57ed03, which is part of version 1.8.2.

At a glance

Exploitability: Can be exploited locally on the machine without logging in, but needs a user to act. High risk of service disruption.
Exploit odds: 0.2% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2026-04-13 23:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-10-26 21:10 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 0.2% in the next 30 days (EPSS).
Severity: 6.1 MEDIUM (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2026-04-13 23:16 UTC
Last modified: 2026-10-26 21:10 UTC
Exploit probability: 0.2% · EPSS, next 30 days
Weakness: CWE-125 · Out-of-bounds read
Record status: Modified

Affected

Jqlang Jq < 2026-04-08

Attack profile CVSS 3.1 · 6.1

Attack vector: Local
Complexity: Low
Privileges needed: None
User interaction: Required
Scope: Unchanged
Confidentiality: Low
Integrity: None
Availability: High

Raw vector

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-39956.md and follow it. Check whether this project is affected by CVE-2026-39956. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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Fix and advisories

References

NVD record · CVE.org record