Reference page — cumulative record through Sunday, October 4, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.

CVE-2026-39956

CVE-2026-39956MEDIUM

jqlang jq — jq: Missing runtime type checks for _strindices lead to crash and limited memory disclosure

  AV  AC  PR  UI  S  C  I  A   CVSS    EPSS   %ile   KEV
   L   L   N   R  U  L  N  H    6.1   .0016    5.1     —

AFFECTED
  Product  Versions   Fixed
  jq       < 1.8.2 –  —

TIMELINE
  Apr 7   Reserved by GitHub_M
  Apr 13  Published (CNA: GitHub_M)
  Sep 4   EXPLOIT PUBLISHED — CVE-2026-39956 (jqlang jq). Public exploit reference added.

CWE-125, CWE-476, CWE-843 · CNA: GitHub_M · CVSS v3.1 · 2 references · NVD status: Modified

Description

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.

Lifecycle

Complete event history — 3 events, chronological
Date	Event	Detail
April 7, 2026	Reserved	Reserved by GitHub_M
April 13, 2026	Published	Published (CNA: GitHub_M)
September 4, 2026	EXPLOIT PUBLISHED	EXPLOIT PUBLISHED — CVE-2026-39956 (jqlang jq). Public exploit reference added.

Affected

Affected products and packages — 1 row
Vendor	Product / Package	Ecosystem	Version introduced	Fixed
jqlang	jq	—	< 1.8.2	—

Weaknesses

CWE-125 · CWE-476 · CWE-843

References (2)

https://github.com/jqlang/jq/commit/fdf8ef0f0810e3d365cdd5160de43db46f57ed03 [Patch]
https://github.com/jqlang/jq/security/advisories/GHSA-6gc3-3g9p-xx28 [Exploit, Vendor Advisory]

Authoritative record: CVE-2026-39956 at cve.org

Vendors: jqlang

Weaknesses: CWE-125 · CWE-476 · CWE-843

About this page

This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-39956 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Sunday, October 4, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.