Skip to main content
No exploitation reported

CVE-2026-16554

Integer Overflow Leading to Heap Buffer Overflow in cJSON

No exploitation reported by the sources we read.

  • Published2026-07-27
  • WeaknessCWE-190

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

cJSON library is vulnerable to an integer overflow in the print_string_ptr() function in cJSON.c on 32-bit platforms. The escape_characters counter, a 32-bit size_t, can wrap around when processing strings containing approximately 858,993,460 or more control characters, causing the output buffer to be allocated based on an underestimated length. When cJSON_PrintBuffered() is used with a pre-allocated buffer, the subsequent write loop overflows the heap allocation. An attacker supplying a crafted JSON string to an application using cJSON on a 32-bit platform can cause a heap buffer overflow, potentially leading to remote code execution, information disclosure, or denial of service. Because project creator contact attempts were unsuccessful, the vulnerability has only been confirmed in version 1.7.19 but may also affect other versions.

Timeline

dates in UTC
  1. 2026-07-2709:16CVE publishedNVD

Versions per branch

NVD
Davegamble cjson
BranchAffectedFixed in
1.7= 1.7.19no fix published

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Products declared by the CNA1 product

As CERT-PL, the CNA that assigned this CVE, declared them in the CVE record; versions as written.

Source: the CNA record (CVE Program), © The MITRE Corporation,CVE Terms of UseCVE recordupdated 2026-07-27

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • apparmorAzure Linux:3all versions · no fixed version listedand 1 other package
  • cjsonUbuntu:Pro:24.04:LTSall versions · no fixed version listed
  • cjsonUbuntu:Pro:22.04:LTSall versions · no fixed version listed
  • cjsonUbuntu:Pro:20.04:LTSall versions · no fixed version listed
  • cjsonUbuntu:26.10all versions · no fixed version listed
  • cjsonUbuntu:26.04:LTSall versions · no fixed version listed
  • cjsonRoot:Alpine:3.23all versions · fixed in 1.7.19-r10071and 1 other package
  • cjsonRoot:Alpine:3.23all versions · fixed in 1.7.19-r10072and 1 other package

7 more package ranges on OSV.dev

Vendor advisories

  • CVE-2026-16554 Red Hat Product Security

    cJSON: cJSON: Remote code execution due to integer overflow via crafted JSON

Full record on NVD

Fix

No fix published by the sources we read yet. NVD record

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CVSS 4.0 vector
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:L/SI:L/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Published
2026-07-27
Last Modified
2026-10-24
NVD status
Analyzed
GitHub Advisory
GHSA-qv6q-8g2j-w47g

Frequently asked questions

What is CVE-2026-16554?

cJSON library is vulnerable to an integer overflow in the print_string_ptr() function in cJSON.c on 32-bit platforms. The escape_characters counter, a 32-bit size_t, can wrap around when processing strings containing approximately 858,993,460 or more control characters, causing the output buffer to be allocated based on an underestimated length. When cJSON_PrintBuffered() is used with a pre-allocated buffer, the subsequent write loop overflows the heap allocation. An attacker supplying a crafted JSON string to an application using cJSON on a 32-bit platform can cause a heap buffer overflow, potentially leading to remote code execution, information disclosure, or denial of service. Because project creator contact attempts were unsuccessful, the vulnerability has only been confirmed in version 1.7.19 but may also affect other versions.

Is CVE-2026-16554 actively exploited?

Active exploitation of CVE-2026-16554 has not been confirmed. Its EPSS score was 0.4% on 2026-11-08, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-16554?

CVE-2026-16554 has a CVSS v3 base score of 7.8 (HIGH severity), with vector string CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

Running cJSON? Hear about its next vulnerability

Surveillance reads the versions in your stack — a domain, a lockfile or a list — checks each CVE against the ranges its sources publish, and alerts you when one you run is exploited or enters CISA KEV. A version it cannot read stays « version not verified ».

Get alerts for this productCISA KEV additions, November 2026Search CVEs

No credit card required · No monthly cap on website lookups · 250 API requests/month

Go further

Related vulnerabilities

Same product first, then the same vendor advisory and the same publication week.

Back to CVE Database

Sources for this record