CVE-2026-29036Public exploitNetwork attack vector

Wrong-key modification via JSON Pointer misdecoding

Published Aug 11, 2026 · Updated Aug 11, 2026

Incorrect JSON Pointer resolution in cJSON 1.5.0 through 1.7.19 allows remote attackers to modify unintended object keys via JSON Patch input. In decode_pointer_inplace(), the ~1 branch writes a slash to decoded_string[1] instead of the current output position, silently resolving crafted paths to the wrong key. Exposure requires an application to pass attacker-controlled patches to the affected helpers; exploitation corrupts or deletes unintended data, while authorization impact depends on application logic.

CVSS severity8.7
High
EPSS probability0.26%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incorrect JSON Pointer resolution in cJSON 1.5.0 through 1.7.19 allows remote attackers to modify unintended object keys via JSON Patch input. In decode_pointer_inplace(), the ~1 branch writes a slash to decoded_string[1] instead of the current output position, silently resolving crafted paths to the wrong key. Exposure requires an application to pass attacker-controlled patches to the affected helpers; exploitation corrupts or deletes unintended data, while authorization impact depends on application logic.

The record

CVE
CVE-2026-29036
Published
Aug 11, 2026
Updated
Aug 11, 2026
Vendor
cJSON Project
Product
cJSON
Classifications
CWE-706, T1565.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 11, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 11, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1.5.0 <=1.7.19

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

cJSON Project · cJSONversion=1.5.0 <=1.7.19

Published CVSS scores

7.5VulnCheckCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
8.7VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-706Use of Incorrectly-Resolved Name or Reference
T1565.001Stored Data Manipulation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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