CVE-2026-87933

DaveGamble cJSON cJSON_Utils.c cJSONUtils_MergePatch use after free

Published Sep 10, 2026 CVSS 4.0 · 6.9 Medium EPSS < 1% KEV · Not listed

Description

A vulnerability was found in DaveGamble cJSON up to 1.7.19. The affected element is the function cJSONUtils_MergePatch of the file cJSON_Utils.c. The manipulation results in use after free. The attack may be launched remotely. The exploit has been made public and could be used. The pull request to fix this issue awaits acceptance.

Analysis

Technical impact

The vulnerability resides in the cJSONUtils_MergePatch function within DaveGamble's cJSON library. When a crafted JSON input is processed, the function frees memory and then attempts to access that freed memory, creating a use‑after‑free condition. This can lead to memory corruption, application crashes, or potentially unintended execution of code, though the CVE description does not confirm arbitrary code execution.

Affected Systems

All released versions of DaveGamble cJSON from the initial release through version 1.7.19 are affected. Versions beyond 1.7.19 have not been verified to contain the fix and should be considered at risk until a patch is applied.

Risk and Exploitability

The CVSS score of 6.9 signals moderate severity, the EPSS score of less than 1% indicates low exposure probability, and the vulnerability is not listed in the CISA KEV catalog. Nevertheless, the exploit is public and can be triggered over a remote interface, which raises the potential risk for any system that uses an unpatched copy of the library.

Affected Products

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

DaveGamble

cJSON

affected

Version	Status	Constraints
`1.7.0`	affected	—
`1.7.1`	affected	—
`1.7.2`	affected	—
`1.7.3`	affected	—
`1.7.4`	affected	—
`1.7.5`	affected	—
`1.7.6`	affected	—
`1.7.7`	affected	—
`1.7.8`	affected	—
`1.7.9`	affected	—
`1.7.10`	affected	—
`1.7.11`	affected	—
`1.7.12`	affected	—
`1.7.13`	affected	—
`1.7.14`	affected	—
`1.7.15`	affected	—
`1.7.16`	affected	—
`1.7.17`	affected	—
`1.7.18`	affected	—
`1.7.19`	affected	—

No data.

Vendor Product Versions

Davegamble

Cjson

Version	Status	Scheme	Platform
`1.7.0`	affected	semver	—
`1.7.1`	affected	semver	—
`1.7.2`	affected	semver	—
`1.7.3`	affected	semver	—
`1.7.4`	affected	semver	—
`1.7.5`	affected	semver	—
`1.7.6`	affected	semver	—
`1.7.7`	affected	semver	—
`1.7.8`	affected	semver	—
`1.7.9`	affected	semver	—
`1.7.10`	affected	semver	—
`1.7.11`	affected	semver	—
`1.7.12`	affected	semver	—
`1.7.13`	affected	semver	—
`1.7.14`	affected	semver	—
`1.7.15`	affected	semver	—
`1.7.16`	affected	semver	—
`1.7.17`	affected	semver	—
`1.7.18`	affected	semver	—
`1.7.19`	affected	semver	—

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

Apply the official upgrade to a cJSON release that merges the security fix, addressing the use‑after‑free (CWE‑416) and related buffer issues (CWE‑119).
If an upgrade is not feasible immediately, remove or disable all calls to cJSONUtils_MergePatch in your code base, thereby eliminating the unsafe memory access and any associated integer wrap‑around (CWE‑825).
Continuously monitor the cJSON GitHub repository and vendor advisories, and install any subsequent patches or updates as soon as they become available.

Generated by OpenCVE AI on September 21, 2026 at 06:21 UTC.

Tracking

Advisories

No advisories available

Metrics

Attack Vector Network

Attack Complexity Low

Privileges Required None

Attack Requirements None

User Interaction None

Vulnerable System Confidentiality Impact Low

Vulnerable System Integrity Impact Low

Vulnerable System Availability Impact Low

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact Low

Integrity Impact Low

Availability Impact Low

User Interaction None

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact Low

Integrity Impact Low

Availability Impact Low

User Interaction None

Access Vector Network

Access Complexity Low

Authentication None

Confidentiality Impact Partial

Integrity Impact Partial

Availability Impact Partial

This CVE is not in the KEV list.

Exploit prediction score: < 1% (0.527% probability within 30 days)

Exploitation poc

Automatable yes

Technical Impact partial

References

Link	Providers
https://github.com/DaveGamble/cJSON/
https://github.com/DaveGamble/cJSON/issues/1060
https://github.com/DaveGamble/cJSON/pull/1065
https://nvd.nist.gov/vuln/detail/CVE-2026-87933
https://vuldb.com/cve/CVE-2026-87933
https://vuldb.com/submit/911136
https://vuldb.com/vuln/401815
https://vuldb.com/vuln/401815/cti
https://www.cve.org/CVERecord?id=CVE-2026-87933

History

Sep 12, 2026 12:15 AM Weaknesses updated. Added references. Scoring metrics updated View changes

Type	Values Removed	Values Added
Weaknesses		CWE-825
References		https://nvd.nist.gov/vuln/detail/CVE-2026-87933 https://www.cve.org/CVERecord?id=CVE-2026-87933
Metrics	threat_severity `None`	threat_severity `Important`

Sep 10, 2026 8:30 PM Scoring metrics updated View changes

Type	Values Removed	Values Added
Metrics		ssvc `{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}`

Sep 10, 2026 1:00 AM Description updated. Title updated. First appearance in the feed. Weaknesses updated. Affected versions updated. Affected vendors updated. Added references. Scoring metrics updated View changes

Type	Values Removed	Values Added
Description		A vulnerability was found in DaveGamble cJSON up to 1.7.19. The affected element is the function cJSONUtils_MergePatch of the file cJSON_Utils.c. The manipulation results in use after free. The attack may be launched remotely. The exploit has been made public and could be used. The pull request to fix this issue awaits acceptance.
Title		DaveGamble cJSON cJSON_Utils.c cJSONUtils_MergePatch use after free
First Time appeared		Davegamble Davegamble cjson
Weaknesses		CWE-119 CWE-416
CPEs		cpe:2.3:a:davegamble:cjson::::::::
Vendors & Products		Davegamble Davegamble cjson
References		https://github.com/DaveGamble/cJSON/ https://github.com/DaveGamble/cJSON/issues/1060 https://github.com/DaveGamble/cJSON/pull/1065 https://vuldb.com/cve/CVE-2026-87933 https://vuldb.com/submit/911136 https://vuldb.com/vuln/401815 https://vuldb.com/vuln/401815/cti
Metrics		cvssV2_0 `{'score': 7.5, 'vector': 'AV:N/AC:L/Au:N/C:P/I:P/A:P/E:POC/RL:ND/RC:UR'}` cvssV3_0 `{'score': 7.3, 'vector': 'CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L/E:P/RL:X/RC:R'}` cvssV3_1 `{'score': 7.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L/E:P/RL:X/RC:R'}` cvssV4_0 `{'score': 6.9, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P'}`

Subscriptions

Davegamble Cjson

Weaknesses

CWE-119
Improper Restriction of Operations within the Bounds of a Memory Buffer
CWE-416
Use After Free
CWE-825
Expired Pointer Dereference

Sources

CVE record Updated: Sep 10, 2026, 7:06 PM

Status: PUBLISHED
Assigner: VulDB
Published: Sep 10, 2026, 12:15 AM
Updated: Sep 10, 2026, 7:06 PM
Reserved: Sep 9, 2026, 4:21 PM

View source JSON

Vulnrichment Updated: Sep 10, 2026, 6:13 PM

Updated: Sep 10, 2026, 6:13 PM

JSON

NVD Updated: Sep 10, 2026, 8:17 PM

Status: Deferred
Published: Sep 10, 2026, 1:16 AM
Modified: Sep 10, 2026, 8:17 PM

View source JSON

Red Hat Updated: Sep 10, 2026, 12:15 AM

Severity: Important
Public date: Sep 10, 2026, 12:15 AM

View source Bugzilla JSON

OpenCVE enrichment Updated: Sep 21, 2026, 6:30 AM

Updated: Sep 21, 2026, 6:30 AM

JSON

Analysis

Technical impact

Affected Systems

Risk and Exploitability

Affected Products

Remediation

Tracking

Advisories

Metrics

Attack Vector Network

Attack Complexity Low

Privileges Required None

Attack Requirements None

User Interaction None

Vulnerable System Confidentiality Impact Low

Vulnerable System Integrity Impact Low

Vulnerable System Availability Impact Low

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact Low

Integrity Impact Low

Availability Impact Low

User Interaction None

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact Low

Integrity Impact Low

Availability Impact Low

User Interaction None

Access Vector Network

Access Complexity Low

Authentication None

Confidentiality Impact Partial

Integrity Impact Partial

Availability Impact Partial

Exploitation poc

Automatable yes

Technical Impact partial

Subscriptions

Sources

JSON object

JSON object

JSON object

JSON object

JSON object