{
  "affected": [
    {
      "ecosystem_specific": {
        "urgency": "not yet assigned"
      },
      "package": {
        "ecosystem": "Debian:12",
        "name": "dia"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "ecosystem_specific": {
        "urgency": "not yet assigned"
      },
      "package": {
        "ecosystem": "Debian:13",
        "name": "dia"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "ecosystem_specific": {
        "urgency": "not yet assigned"
      },
      "package": {
        "ecosystem": "Debian:14",
        "name": "dia"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "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": "DEBIAN-CVE-2026-77658",
  "modified": "2026-09-14T16:47:38.227039290Z",
  "published": "2026-08-26T13:19:22.043Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://security-tracker.debian.org/tracker/CVE-2026-77658"
    }
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "upstream": [
    "CVE-2026-77658"
  ]
}