CVE-2026-39956

jq is a command-line JSON processor. In commits after 69785bf77f86e2ea1b4a20ca86775916889e91c9, the strindices builtin in jq's src/builtin.c passes its arguments directly to jvstringindexes() without verifying they are strings, and jvstring_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.

Database specific

{
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/39xxx/CVE-2026-39956.json",
    "cwe_ids": [
        "CWE-125",
        "CWE-476",
        "CWE-843"
    ],
    "unresolved_ranges": [
        {
            "extracted_events": [
                {
                    "introduced": "69785bf77f86e2ea1b4a20ca86775916889e91c9"
                },
                {
                    "fixed": "fdf8ef0f0810e3d365cdd5160de43db46f57ed03"
                }
            ],
            "source": "AFFECTED_FIELD"
        }
    ],
    "cna_assigner": "GitHub_M"
}

References

Affected packages

Git / github.com/jqlang/jq

Affected ranges

Type

GIT

Repo

https://github.com/jqlang/jq

Events

Introduced

Fixed

fdf8ef0f0810e3d365cdd5160de43db46f57ed03

Database specific

{
    "source": "REFERENCES"
}

Affected versions

1.*

1.6rc2

jq-1.*

jq-1.0

jq-1.1

jq-1.2

jq-1.3

jq-1.4

jq-1.5rc1

jq-1.5rc2

jq-1.6

jq-1.6rc1

jq-1.7

jq-1.7.1

jq-1.7rc1

jq-1.7rc2

jq-1.8.0

jq-1.8.1

Database specific

source

"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-39956.json"