# CVE-2026-29036 — DaveGamble cJSON

> As of 2026-08-11, CVE-2026-29036 is a HIGH-severity vulnerability in DaveGamble cJSON, CVSS v3.1 7.5, EPSS 0.2% (17.5th percentile). No Threadlinqs-tracked threat campaign has been attributed to CVE-2026-29036 as of 2026-08-11; the identifier is re-checked against the Threadlinqs threat corpus on every daily ingest.

**Last updated:** 2026-08-11

## What is CVE-2026-29036?

cJSON versions 1.5.0 through 1.7.19 contain an incorrectly-resolved name or reference vulnerability in the decode_pointer_inplace() function within cJSON_Utils.c that allows unauthenticated attackers to cause JSON Patch operations to target wrong object keys by supplying crafted JSON Pointer escape sequences (~0 or ~1) in patch paths. Attackers can submit malicious RFC 6902 JSON Patch input to applications using cJSONUtils_ApplyPatches() or cJSONUtils_ApplyPatchesCaseSensitive() to silently corrupt data or delete unintended keys, potentially bypassing authorization controls in applications that rely on JSON Patch for access-controlled data modification.

The record classifies CVE-2026-29036 under weakness class [CWE-706](https://cwe.mitre.org/data/definitions/706.html). Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs no user interaction, and has high impact on integrity. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 55 days ago.

## Severity and exploitation probability

- **CVSS v3.1 base score:** 7.5 — HIGH (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N`)
- **CVSS v4.0 base score:** 8.7 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N`)
- **EPSS (FIRST):** 0.2% probability of exploitation in the next 30 days, higher than 17.5% of all scored CVEs
- **CISA KEV:** Not listed in the CISA Known Exploited Vulnerabilities catalog
- **Threadlinqs priority:** 4.5/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- **Published:** 2026-08-11

## Is CVE-2026-29036 being exploited?

It currently carries a trending score of 34 in the Threadlinqs vulnerability feed.

## Affected products and versions

- **DaveGamble**: cJSON

## How to fix CVE-2026-29036

No vendor patch reference has been recorded for CVE-2026-29036 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.

## Threat activity tracking CVE-2026-29036

No threat campaign in the Threadlinqs corpus currently references CVE-2026-29036, in its CVE list or as an indicator. The linkage is recomputed from the live corpus on every daily ingest, so this section fills in as soon as a tracked campaign cites the identifier.

## Sources

Enriched from CVE.org, NVD, FIRST EPSS, GitHub Security Advisories. Last verified by Threadlinqs on 2026-08-13. This product uses the NVD API but is not endorsed or certified by the NVD.

**Third-party advisory**

- [vulncheck.com — third party advisory](https://www.vulncheck.com/advisories/cjson-wrong-key-modification-via-json-pointer-escape-decoding)

**Issue tracking and product pages**

- [github.com — product](https://github.com/DaveGamble/cJSON)

Canonical: https://intel.threadlinqs.com/cve/CVE-2026-29036
Full detection coverage and IOCs for threats exploiting CVE-2026-29036 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp