FKIE_CVE-2026-9499

Vulnerability from fkie_nvd - Published: 2026-07-21 14:16 - Updated: 2026-07-21 14:16
Severity
6.3 (Medium) - CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N
Summary
An out-of-bounds read (buffer over-read) vulnerability exists in QTextCodec::codecForName() in Qt. When the function is called with a QByteArray that is not NUL-terminated (for example, one created with QByteArray::fromRawData()), the codec-name matching routine reads past the end of the supplied buffer. In most cases this results in an incorrect text codec being selected; in the worst case, if the over-read reaches unmapped memory, the process crashes (denial of service). The over-read is bounded by the length of the longest codec-name candidate, and the out-of-bounds bytes are only compared internally against Qt's fixed list of codec names, so no data is disclosed to an attacker. Applications that do not pass non-NUL-terminated QByteArrays to QTextCodec::codecForName() are not exposed. The affected code resides in the Qt5Compat module from Qt 6.0.0 onward, and in Qt Core (qtbase) in Qt 4.x and Qt 5.x.
References
a59d8014-47c4-4630-ab43-e1b13cbe58e3https://codereview.qt-project.org/c/qt/qt5compat/+/723911
a59d8014-47c4-4630-ab43-e1b13cbe58e3https://codereview.qt-project.org/c/qt/qt5compat/+/724348
a59d8014-47c4-4630-ab43-e1b13cbe58e3https://codereview.qt-project.org/c/qt/qt5compat/+/724995
a59d8014-47c4-4630-ab43-e1b13cbe58e3https://codereview.qt-project.org/c/qt/tqtc-qt5compat/+/725112
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "cpes": [
            "cpe:2.3:a:qt:qt:*:*:*:*:*:*:*:*"
          ],
          "defaultStatus": "unaffected",
          "modules": [
            "Qt5Compat (Core5Compat)"
          ],
          "product": "Qt",
          "vendor": "Qt",
          "versions": [
            {
              "lessThan": "6.8.8",
              "status": "affected",
              "version": "6.0.0",
              "versionType": "python"
            },
            {
              "lessThan": "6.11.1",
              "status": "affected",
              "version": "6.9.0",
              "versionType": "python"
            }
          ]
        },
        {
          "cpes": [
            "cpe:2.3:a:qt:qt:*:*:*:*:*:*:*:*"
          ],
          "defaultStatus": "unaffected",
          "modules": [
            "qtbase"
          ],
          "product": "Qt",
          "vendor": "Qt",
          "versions": [
            {
              "lessThan": "6.0.0",
              "status": "affected",
              "version": "4.0.0",
              "versionType": "python"
            }
          ]
        }
      ],
      "source": "a59d8014-47c4-4630-ab43-e1b13cbe58e3"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "An out-of-bounds read (buffer over-read) vulnerability exists in QTextCodec::codecForName() in Qt. When the function is called with a QByteArray that is not NUL-terminated (for example, one created with QByteArray::fromRawData()), the codec-name matching routine reads past the end of the supplied buffer. In most cases this results in an incorrect text codec being selected; in the worst case, if the over-read reaches unmapped memory, the process crashes (denial of service). The over-read is bounded by the length of the longest codec-name candidate, and the out-of-bounds bytes are only compared internally against Qt\u0027s fixed list of codec names, so no data is disclosed to an attacker. Applications that do not pass non-NUL-terminated QByteArrays to QTextCodec::codecForName() are not exposed. The affected code resides in the Qt5Compat module from Qt 6.0.0 onward, and in Qt Core (qtbase) in Qt 4.x and Qt 5.x."
    }
  ],
  "id": "CVE-2026-9499",
  "lastModified": "2026-07-21T14:16:35.843",
  "metrics": {
    "cvssMetricV40": [
      {
        "cvssData": {
          "Automatable": "NOT_DEFINED",
          "Recovery": "NOT_DEFINED",
          "Safety": "NOT_DEFINED",
          "attackComplexity": "LOW",
          "attackRequirements": "PRESENT",
          "attackVector": "NETWORK",
          "availabilityRequirement": "NOT_DEFINED",
          "baseScore": 6.3,
          "baseSeverity": "MEDIUM",
          "confidentialityRequirement": "NOT_DEFINED",
          "exploitMaturity": "NOT_DEFINED",
          "integrityRequirement": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
          "modifiedAttackRequirements": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "privilegesRequired": "NONE",
          "providerUrgency": "NOT_DEFINED",
          "subAvailabilityImpact": "NONE",
          "subConfidentialityImpact": "NONE",
          "subIntegrityImpact": "NONE",
          "userInteraction": "NONE",
          "valueDensity": "NOT_DEFINED",
          "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N/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",
          "version": "4.0",
          "vulnAvailabilityImpact": "LOW",
          "vulnConfidentialityImpact": "NONE",
          "vulnIntegrityImpact": "LOW",
          "vulnerabilityResponseEffort": "NOT_DEFINED"
        },
        "source": "a59d8014-47c4-4630-ab43-e1b13cbe58e3",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-07-21T14:16:35.843",
  "references": [
    {
      "source": "a59d8014-47c4-4630-ab43-e1b13cbe58e3",
      "url": "https://codereview.qt-project.org/c/qt/qt5compat/+/723911"
    },
    {
      "source": "a59d8014-47c4-4630-ab43-e1b13cbe58e3",
      "url": "https://codereview.qt-project.org/c/qt/qt5compat/+/724348"
    },
    {
      "source": "a59d8014-47c4-4630-ab43-e1b13cbe58e3",
      "url": "https://codereview.qt-project.org/c/qt/qt5compat/+/724995"
    },
    {
      "source": "a59d8014-47c4-4630-ab43-e1b13cbe58e3",
      "url": "https://codereview.qt-project.org/c/qt/tqtc-qt5compat/+/725112"
    }
  ],
  "sourceIdentifier": "a59d8014-47c4-4630-ab43-e1b13cbe58e3",
  "vulnStatus": "Received",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-125"
        }
      ],
      "source": "a59d8014-47c4-4630-ab43-e1b13cbe58e3",
      "type": "Secondary"
    }
  ]
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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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.


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