Vulnerability-Lookup

UBUNTU-CVE-2026-16554 (CVE-2026-16554)

Vulnerability from osv_ubuntu – Published: 2026-07-27 09:16 – Updated: 2026-08-31 14:18 – Source website

Details

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.

Severity

5.1 (Medium)


                    
                      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

7.8 (High)


                    
                      CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

N/A (UNKNOWN)


                    
                      medium

References

URL

Type

	https://ubuntu.com/security/CVE-2026-16554	REPORT
	https://www.cve.org/CVERecord?id=CVE-2026-16554	REPORT
	https://cert.pl/en/posts/2026/07/CVE-2026-16554	REPORT
	https://github.com/DaveGamble/cJSON	REPORT

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libcjson1",
            "binary_version": "1.7.10-1.1ubuntu0.1~esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:20.04:LTS",
        "name": "cjson",
        "purl": "pkg:deb/ubuntu/cjson@1.7.10-1.1ubuntu0.1~esm1?arch=source\u0026distro=esm-apps/focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.7.10-1.1",
        "1.7.10-1.1ubuntu0.1~esm1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libcjson1",
            "binary_version": "1.7.15-1ubuntu0.1+esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:22.04:LTS",
        "name": "cjson",
        "purl": "pkg:deb/ubuntu/cjson@1.7.15-1ubuntu0.1+esm1?arch=source\u0026distro=esm-apps/jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.7.14-1",
        "1.7.15-1",
        "1.7.15-1ubuntu0.1~esm2",
        "1.7.15-1ubuntu0.1",
        "1.7.15-1ubuntu0.1+esm1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libcjson1",
            "binary_version": "1.7.17-1ubuntu0.1~esm3"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:24.04:LTS",
        "name": "cjson",
        "purl": "pkg:deb/ubuntu/cjson@1.7.17-1ubuntu0.1~esm3?arch=source\u0026distro=esm-apps/noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.7.16-1",
        "1.7.16-2",
        "1.7.17-1",
        "1.7.17-1ubuntu0.1~esm2",
        "1.7.17-1ubuntu0.1~esm3"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libcjson1",
            "binary_version": "1.7.19-2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "cjson",
        "purl": "pkg:deb/ubuntu/cjson@1.7.19-2?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.7.18-3.1",
        "1.7.18-4",
        "1.7.19-1",
        "1.7.19-2"
      ]
    }
  ],
  "aliases": [],
  "details": "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.",
  "id": "UBUNTU-CVE-2026-16554",
  "modified": "2026-08-31T14:18:41Z",
  "published": "2026-07-27T09:16:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-16554"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-16554"
    },
    {
      "type": "REPORT",
      "url": "https://cert.pl/en/posts/2026/07/CVE-2026-16554"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/DaveGamble/cJSON"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "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",
      "type": "CVSS_V4"
    },
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-16554"
  ]
}

CVE-2026-16554 (GCVE-0-2026-16554)

Vulnerability from cvelistv5 – Published: 2026-07-27 08:40 – Updated: 2026-07-31 13:34 X_Open Source

Title

Integer Overflow Leading to Heap Buffer Overflow in cJSON

Summary

Severity

5.1 (Medium)


                        
                          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

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-07-27 10:24 UTC

CWE

CWE-190 - Integer overflow or wraparound

Assigner

CERT-PL ENISA root

References

4 references

URL	Tags
https://cert.pl/en/posts/2026/07/CVE-2026-16554	third-party-advisory
https://github.com/DaveGamble/cJSON	product
http://www.openwall.com/lists/oss-security/2026/0…
http://www.openwall.com/lists/oss-security/2026/07/31/4

Impacted products

1 product

Vendor	Product	Version
DaveGamble	cJSON	Affected: 1.7.19 (semver)

Credits

Michał Majchrowicz (AFINE Team) Marcin Wyczechowski (AFINE Team)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-16554",
                "options": [
                  {
                    "Exploitation": "none"
                  },
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                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-07-27T10:24:13.881075Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-07-27T10:24:23.056Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      },
      {
        "providerMetadata": {
          "dateUpdated": "2026-07-31T13:34:05.448Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
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          },
          {
            "url": "http://www.openwall.com/lists/oss-security/2026/07/31/4"
          }
        ],
        "title": "CVE Program Container"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "modules": [
            "cJSON.c"
          ],
          "product": "cJSON",
          "repo": "https://github.com/DaveGamble/cJSON",
          "vendor": "DaveGamble",
          "versions": [
            {
              "status": "affected",
              "version": "1.7.19",
              "versionType": "semver"
            }
          ]
        }
      ],
      "configurations": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "32-bit platforms"
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          ],
          "value": "32-bit platforms"
        }
      ],
      "credits": [
        {
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          "type": "finder",
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        },
        {
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        }
      ],
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      "metrics": [
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            "Recovery": "NOT_DEFINED",
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            "attackRequirements": "NONE",
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            "baseScore": 5.1,
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          "descriptions": [
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              "lang": "en",
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      "providerMetadata": {
        "dateUpdated": "2026-07-27T08:40:17.183Z",
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          "url": "https://github.com/DaveGamble/cJSON"
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    "dateReserved": "2026-07-22T11:49:39.961Z",
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    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
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}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
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Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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UBUNTU-CVE-2026-16554 (CVE-2026-16554)

CVE-2026-16554 (GCVE-0-2026-16554)

Tags

Sightings

Nomenclature

Related by attack behaviour