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CVE-2026-77652

Status: Awaiting AnalysisHigh (7.8)—

A heap-based buffer overflow vulnerability exists in the Dia diagram editor WPG file format importer.

In plug-ins/wpg/wpg-import.c, the WPG import renderer allocates a fixed palette with:

When handling a WPG_COLORMAP record, the parser reads a start index (i16) and number of colors (iNum16) from the file and reads palette data with:

The only bounds-related check is `if (i16 >= 0 && i16 <= iSize)`, where iSize is the WPG record size—not the palette capacity. There is no validation that i16 is less than 256 or that i16 + iNum16 does not exceed 256.

A malicious WPG file can supply i16=256 and iNum16=264. That causes fread() to write 792 bytes starting at &pPal[256], while the palette buffer is only 768 bytes (256 entries × 3 bytes).

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This overflows into adjacent heap metadata and can crash Dia (SIGABRT / malloc corruption errors) or, depending on heap layout and exploit primitives, potentially lead to arbitrary code execution.

Exploitation requires convincing a user to open a crafted WPG file via Dia's file dialog, command line, or file association. No special privileges are required to deliver the file to the victim.

Affected component: WPG parser (plug-ins/wpg/wpg-import.c). Affected versions: all Dia versions containing this code path (reporter tested Dia 0.98+git20260221-1; issue present on upstream master as of 2026-08-21).

Technical details traces, logs and code from the original report
    ren->pPal = g_new0(WPGColorRGB, 256);

    bRet &= (iNum16 == (int)fread(&ren->pPal[i16], sizeof(WPGColorRGB), iNum16, f));

CVSS

Exploitation probability (EPSS)

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

🎯 ATT&CK techniques

How this vulnerability is exploited and what the attacker gains, in MITRE ATT&CK terms.

Buffer overflow en importador WPG requiere que usuario abra archivo malicioso (UI:R, AV:L → T1203). Potencial RCE (ejecución código) o DoS por corrupción de heap (crash/SIGABRT).

Inferred by our analysis agent from the official description, CVSS vector and CWE, and checked by a supervisor. May contain errors.

🛡️ ATT&CK mitigations that cover these techniques

Restrict Web-Based ContentPrivileged Account ManagementLimit Software InstallationFilter Network TrafficExecution PreventionBehavior Prevention on Endpoint

Affected technologies (1)

⚠ AI-inferred from the description — NVD hasn't analyzed this CVE yet, these aren't verified CPEs.

DIA — DIAAI

CWEs

References

Raw JSON (NVD)

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{
  "id": "CVE-2026-77652",
  "cveTags": [],
  "metrics": {
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-77652",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "poc"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2026-08-27T14:42:56.357247Z"
        }
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "patrick@puiterwijk.org",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 7.8,
          "attackVector": "LOCAL",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "REQUIRED",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.9,
        "exploitabilityScore": 1.8
      }
    ]
  },
  "affected": [
    {
      "source": "patrick@puiterwijk.org",
      "affectedData": [
        {
          "vendor": "GNOME",
          "product": "Dia",
          "versions": [
            {
              "status": "affected",
              "version": "0",
              "versionType": "semver",
              "lessThanOrEqual": "0.98+git20260221-1"
            }
          ],
          "packageName": "dia",
          "collectionURL": "https://gitlab.gnome.org/GNOME/dia/-/issues/580",
          "defaultStatus": "unaffected"
        }
      ]
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  ],
  "published": "2026-08-26T20:18:02.160",
  "references": [
    {
      "url": "https://access.redhat.com/security/cve/CVE-2026-77652",
      "source": "patrick@puiterwijk.org"
    },
    {
      "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2520884",
      "source": "patrick@puiterwijk.org"
    },
    {
      "url": "https://gitlab.gnome.org/GNOME/dia/-/blob/master/plug-ins/wpg/wpg-import.c",
      "source": "patrick@puiterwijk.org"
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    {
      "url": "https://gitlab.gnome.org/GNOME/dia/-/issues/580",
      "source": "patrick@puiterwijk.org"
    },
    {
      "url": "https://gitlab.gnome.org/GNOME/dia/-/issues/580",
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"
    }
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  "vulnStatus": "Awaiting Analysis",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "patrick@puiterwijk.org",
      "description": [
        {
          "lang": "en",
          "value": "CWE-122"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "A heap-based buffer overflow vulnerability exists in the Dia diagram editor WPG file format importer.\n\nIn plug-ins/wpg/wpg-import.c, the WPG import renderer allocates a fixed palette with:\n\n    ren->pPal = g_new0(WPGColorRGB, 256);\n\nWhen handling a WPG_COLORMAP record, the parser reads a start index (i16) and number of colors (iNum16) from the file and reads palette data with:\n\n    bRet &= (iNum16 == (int)fread(&ren->pPal[i16], sizeof(WPGColorRGB), iNum16, f));\n\nThe only bounds-related check is `if (i16 >= 0 && i16 <= iSize)`, where iSize is the WPG record size—not the palette capacity. There is no validation that i16 is less than 256 or that i16 + iNum16 does not exceed 256.\n\nA malicious WPG file can supply i16=256 and iNum16=264. That causes fread() to write 792 bytes starting at &pPal[256], while the palette buffer is only 768 bytes (256 entries × 3 bytes). This overflows into adjacent heap metadata and can crash Dia (SIGABRT / malloc corruption errors) or, depending on heap layout and exploit primitives, potentially lead to arbitrary code execution.\n\nExploitation requires convincing a user to open a crafted WPG file via Dia's file dialog, command line, or file association. No special privileges are required to deliver the file to the victim.\n\nAffected component: WPG parser (plug-ins/wpg/wpg-import.c).\nAffected versions: all Dia versions containing this code path (reporter tested Dia 0.98+git20260221-1; issue present on upstream master as of 2026-08-21)."
    }
  ],
  "lastModified": "2026-08-28T15:44:39.323",
  "sourceIdentifier": "patrick@puiterwijk.org"
}