Vulnerability-Lookup

ubuntu-cve-2026-77658

Vulnerability from osv_ubuntu

Published

2026-08-26 13:19

Modified

2026-09-02 16:27

Summary

Details

A stack-based buffer overflow vulnerability exists in the Dia diagram editor when processing Network Bus objects from Dia XML project files. In objects/network/bus.c, bus_load() reads the number of bus handles from the file attribute "bus_handles" using attribute_num_data() without validating an upper bound: bus->num_handles = attribute_num_data(attr); When a bus handle is subsequently moved, bus_handle_moved() allocates two temporary arrays on the stack: parallel = (real )g_alloca(num_handles * sizeof(real)); perp = (real )g_alloca(num_handles * sizeof(real)); Because num_handles is fully attacker-controlled via the project file, sufficiently large values (for example 262144 or higher) cause g_alloca() to consume more stack space than the default thread stack limit (typically 8 MB on Linux), resulting in stack overflow, SIGSEGV, and potential stack frame / return-address corruption. An attacker can embed a Bus object with an excessive bus_handles count in a malicious .dia file. Exploitation requires the victim to open the file in Dia (file dialog, command line, or file association) and trigger handle manipulation (moving a bus handle), which exercises the vulnerable code path. The identical g_alloca pattern is present in objects/Misc/tree.c (copied from bus.c) and is likely vulnerable to the same class of attack via Tree objects. Affected versions: Dia 0.98.0 and earlier versions containing this code; issue confirmed on upstream master as of 2026-08-21. Upstream report: https://gitlab.gnome.org/GNOME/dia/-/issues/581

Severity

7.8 (High)


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

N/A (UNKNOWN)


                    
                      medium

References

URL

Type

	https://ubuntu.com/security/CVE-2026-77658	REPORT
	https://www.cve.org/CVERecord?id=CVE-2026-77658	REPORT
	https://gitlab.gnome.org/GNOME/dia/-/issues/581	REPORT

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "dia",
            "binary_version": "0.97.3-1"
          },
          {
            "binary_name": "dia-common",
            "binary_version": "0.97.3-1"
          },
          {
            "binary_name": "dia-gnome",
            "binary_version": "0.97.3-1"
          },
          {
            "binary_name": "dia-libs",
            "binary_version": "0.97.3-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:16.04:LTS",
        "name": "dia",
        "purl": "pkg:deb/ubuntu/dia@0.97.3-1?arch=source\u0026distro=xenial"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.97.3-1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "dia",
            "binary_version": "0.97.3+git20160930-8"
          },
          {
            "binary_name": "dia-common",
            "binary_version": "0.97.3+git20160930-8"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:18.04:LTS",
        "name": "dia",
        "purl": "pkg:deb/ubuntu/dia@0.97.3+git20160930-8?arch=source\u0026distro=bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.97.3+git20160930-6",
        "0.97.3+git20160930-7",
        "0.97.3+git20160930-8"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "dia",
            "binary_version": "0.97.3+git20160930-9"
          },
          {
            "binary_name": "dia-common",
            "binary_version": "0.97.3+git20160930-9"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:20.04:LTS",
        "name": "dia",
        "purl": "pkg:deb/ubuntu/dia@0.97.3+git20160930-9?arch=source\u0026distro=focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.97.3+git20160930-8.1",
        "0.97.3+git20160930-8.2",
        "0.97.3+git20160930-9"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "dia",
            "binary_version": "0.97.3+git20160930-9build1"
          },
          {
            "binary_name": "dia-common",
            "binary_version": "0.97.3+git20160930-9build1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "dia",
        "purl": "pkg:deb/ubuntu/dia@0.97.3+git20160930-9build1?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.97.3+git20160930-9",
        "0.97.3+git20160930-9build1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "dia",
            "binary_version": "0.98+git20240130-1build4"
          },
          {
            "binary_name": "dia-common",
            "binary_version": "0.98+git20240130-1build4"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:24.04:LTS",
        "name": "dia",
        "purl": "pkg:deb/ubuntu/dia@0.98+git20240130-1build4?arch=source\u0026distro=noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.97.3+git20220525-5build1",
        "0.97.3+git20220525-5build2",
        "0.97.3+git20220525-5build3",
        "0.98+git20240130-1",
        "0.98+git20240130-1build2",
        "0.98+git20240130-1build3",
        "0.98+git20240130-1build4"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "dia",
            "binary_version": "0.98+git20260221-1"
          },
          {
            "binary_name": "dia-common",
            "binary_version": "0.98+git20260221-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "dia",
        "purl": "pkg:deb/ubuntu/dia@0.98+git20260221-1?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.98+git20250902-0ubuntu1",
        "0.98+git20250902-0ubuntu2",
        "0.98+git20260221-1"
      ]
    }
  ],
  "aliases": [],
  "details": "A stack-based buffer overflow vulnerability exists in the Dia diagram editor when processing Network Bus objects from Dia XML project files. In objects/network/bus.c, bus_load() reads the number of bus handles from the file attribute \"bus_handles\" using attribute_num_data() without validating an upper bound:     bus-\u003enum_handles = attribute_num_data(attr); When a bus handle is subsequently moved, bus_handle_moved() allocates two temporary arrays on the stack:     parallel = (real *)g_alloca(num_handles * sizeof(real));     perp = (real *)g_alloca(num_handles * sizeof(real)); Because num_handles is fully attacker-controlled via the project file, sufficiently large values (for example 262144 or higher) cause g_alloca() to consume more stack space than the default thread stack limit (typically 8 MB on Linux), resulting in stack overflow, SIGSEGV, and potential stack frame / return-address corruption. An attacker can embed a Bus object with an excessive bus_handles count in a malicious .dia file. Exploitation requires the victim to open the file in Dia (file dialog, command line, or file association) and trigger handle manipulation (moving a bus handle), which exercises the vulnerable code path. The identical g_alloca pattern is present in objects/Misc/tree.c (copied from bus.c) and is likely vulnerable to the same class of attack via Tree objects. Affected versions: Dia 0.98.0 and earlier versions containing this code; issue confirmed on upstream master as of 2026-08-21. Upstream report: https://gitlab.gnome.org/GNOME/dia/-/issues/581",
  "id": "UBUNTU-CVE-2026-77658",
  "modified": "2026-09-02T16:27:47Z",
  "published": "2026-08-26T13:19:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-77658"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-77658"
    },
    {
      "type": "REPORT",
      "url": "https://gitlab.gnome.org/GNOME/dia/-/issues/581"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-77658"
  ]
}

CVE-2026-77658 (GCVE-0-2026-77658)

Vulnerability from cvelistv5 – Published: 2026-08-26 12:10 – Updated: 2026-08-26 13:11

Title

Dia: dia: stack buffer overflow in bus object via unvalidated handle count in project files

Summary

A stack-based buffer overflow vulnerability exists in the Dia diagram editor when processing Network Bus objects from Dia XML project files. In objects/network/bus.c, bus_load() reads the number of bus handles from the file attribute "bus_handles" using attribute_num_data() without validating an upper bound: bus->num_handles = attribute_num_data(attr); When a bus handle is subsequently moved, bus_handle_moved() allocates two temporary arrays on the stack: parallel = (real *)g_alloca(num_handles * sizeof(real)); perp = (real *)g_alloca(num_handles * sizeof(real)); Because num_handles is fully attacker-controlled via the project file, sufficiently large values (for example 262144 or higher) cause g_alloca() to consume more stack space than the default thread stack limit (typically 8 MB on Linux), resulting in stack overflow, SIGSEGV, and potential stack frame / return-address corruption. An attacker can embed a Bus object with an excessive bus_handles count in a malicious .dia file. Exploitation requires the victim to open the file in Dia (file dialog, command line, or file association) and trigger handle manipulation (moving a bus handle), which exercises the vulnerable code path. The identical g_alloca pattern is present in objects/Misc/tree.c (copied from bus.c) and is likely vulnerable to the same class of attack via Tree objects. Affected versions: Dia 0.98.0 and earlier versions containing this code; issue confirmed on upstream master as of 2026-08-21. Upstream report: https://gitlab.gnome.org/GNOME/dia/-/issues/581

Severity

7.8 (High)


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

SSVC

Exploitation: poc Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-26 13:09 UTC

CWE

CWE-121 - Stack-based Buffer Overflow

Assigner

fedora redhat root

References

4 references

URL	Tags
https://access.redhat.com/security/cve/CVE-2026-77658	vdb-entryx_refsource_REDHAT
https://bugzilla.redhat.com/show_bug.cgi?id=2520890	issue-trackingx_refsource_REDHAT
https://gitlab.gnome.org/GNOME/dia/-/blob/master/…
https://gitlab.gnome.org/GNOME/dia/-/issues/581

Impacted products

1 product

Vendor	Product	Version
GNOME	Dia	Affected: 0 , ≤ 0.98.0 (semver)

Date Public

2026-08-21 00:00

Credits

Red Hat would like to thank Robin "drzobin" Larsson for reporting this issue.

Show details on NVD website

JSON

To clipboard

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        "metrics": [
          {
            "other": {
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                "id": "CVE-2026-77658",
                "options": [
                  {
                    "Exploitation": "poc"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-08-26T13:09:44.563034Z",
                "version": "2.0.3"
              },
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            }
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        ],
        "providerMetadata": {
          "dateUpdated": "2026-08-26T13:11:12.732Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
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          "defaultStatus": "unaffected",
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          "product": "Dia",
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      "credits": [
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      ],
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      "descriptions": [
        {
          "lang": "en",
          "value": "A stack-based buffer overflow vulnerability exists in the Dia diagram editor when processing Network Bus objects from Dia XML project files.\n\nIn objects/network/bus.c, bus_load() reads the number of bus handles from the file attribute \"bus_handles\" using attribute_num_data() without validating an upper bound:\n\n    bus-\u003enum_handles = attribute_num_data(attr);\n\nWhen a bus handle is subsequently moved, bus_handle_moved() allocates two temporary arrays on the stack:\n\n    parallel = (real *)g_alloca(num_handles * sizeof(real));\n    perp = (real *)g_alloca(num_handles * sizeof(real));\n\nBecause num_handles is fully attacker-controlled via the project file, sufficiently large values (for example 262144 or higher) cause g_alloca() to consume more stack space than the default thread stack limit (typically 8 MB on Linux), resulting in stack overflow, SIGSEGV, and potential stack frame / return-address corruption.\n\nAn attacker can embed a Bus object with an excessive bus_handles count in a malicious .dia file. Exploitation requires the victim to open the file in Dia (file dialog, command line, or file association) and trigger handle manipulation (moving a bus handle), which exercises the vulnerable code path.\n\nThe identical g_alloca pattern is present in objects/Misc/tree.c (copied from bus.c) and is likely vulnerable to the same class of attack via Tree objects.\n\nAffected versions: Dia 0.98.0 and earlier versions containing this code; issue confirmed on upstream master as of 2026-08-21.\nUpstream report: https://gitlab.gnome.org/GNOME/dia/-/issues/581"
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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.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
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.

Detection rules are retrieved from Rulezet.

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.