CVE-2026-119602

Full vulnerability record from the local CVENow database.

Description

libmspack through 0.11alpha contains an uninitialized memory disclosure vulnerability in the MS-ZIP decompressor that allows attackers to leak heap data via unchecked back-reference distances. Attackers can supply a crafted MS-ZIP CAB file whose first block begins with a back-reference, causing cabd->extract() to write up to 32 KiB of stale heap memory into extracted output.

Severity

MEDIUM

CVSS score

6.3 (v4.0)

Vulnerability status

Deferred

Source identifier

[email protected]

Published

2026-10-30 14:16:48.700000

Last modified

2026-10-30 14:16:48.850000

View original CVE JSON

{
  "id": "CVE-2026-119602",
  "sourceIdentifier": "[email protected]",
  "published": "2026-10-30T14:16:48.700",
  "lastModified": "2026-10-30T14:16:48.850",
  "vulnStatus": "Deferred",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "libmspack through 0.11alpha contains an uninitialized memory disclosure vulnerability in the MS-ZIP decompressor that allows attackers to leak heap data via unchecked back-reference distances. Attackers can supply a crafted MS-ZIP CAB file whose first block begins with a back-reference, causing cabd->extract() to write up to 32 KiB of stale heap memory into extracted output."
    }
  ],
  "affected": [
    {
      "source": "[email protected]",
      "affectedData": [
        {
          "vendor": "kyz",
          "product": "libmspack",
          "defaultStatus": "unaffected",
          "repo": "https://github.com/kyz/libmspack",
          "packageURL": "pkg:github/kyz/libmspack",
          "versions": [
            {
              "version": "0",
              "lessThanOrEqual": "0.11alpha",
              "versionType": "custom",
              "status": "affected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV40": [
      {
        "source": "[email protected]",
        "type": "Secondary",
        "cvssData": {
          "version": "4.0",
          "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/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",
          "baseScore": 6.3,
          "baseSeverity": "MEDIUM",
          "attackVector": "NETWORK",
          "attackComplexity": "LOW",
          "attackRequirements": "PRESENT",
          "privilegesRequired": "NONE",
          "userInteraction": "NONE",
          "vulnConfidentialityImpact": "LOW",
          "vulnIntegrityImpact": "NONE",
          "vulnAvailabilityImpact": "NONE",
          "subConfidentialityImpact": "NONE",
          "subIntegrityImpact": "NONE",
          "subAvailabilityImpact": "NONE",
          "exploitMaturity": "NOT_DEFINED",
          "confidentialityRequirement": "NOT_DEFINED",
          "integrityRequirement": "NOT_DEFINED",
          "availabilityRequirement": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
          "modifiedAttackRequirements": "NOT_DEFINED",
          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "Safety": "NOT_DEFINED",
          "Automatable": "NOT_DEFINED",
          "Recovery": "NOT_DEFINED",
          "valueDensity": "NOT_DEFINED",
          "vulnerabilityResponseEffort": "NOT_DEFINED",
          "providerUrgency": "NOT_DEFINED"
        }
      }
    ],
    "cvssMetricV31": [
      {
        "source": "[email protected]",
        "type": "Primary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N",
          "baseScore": 3.7,
          "baseSeverity": "LOW",
          "attackVector": "NETWORK",
          "attackComplexity": "HIGH",
          "privilegesRequired": "NONE",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "LOW",
          "integrityImpact": "NONE",
          "availabilityImpact": "NONE"
        },
        "exploitabilityScore": 2.2,
        "impactScore": 1.4
      }
    ]
  },
  "weaknesses": [
    {
      "source": "[email protected]",
      "type": "Primary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-908"
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://github.com/kyz/libmspack",
      "source": "[email protected]"
    },
    {
      "url": "https://github.com/kyz/libmspack/blob/v0.11alpha/libmspack/mspack/mszipd.c#L264-L276",
      "source": "[email protected]"
    },
    {
      "url": "https://github.com/kyz/libmspack/issues/60",
      "source": "[email protected]"
    },
    {
      "url": "https://hackmd.io/@haindpwn/libmspack-mszip-uninit-window-info-leak",
      "source": "[email protected]"
    },
    {
      "url": "https://www.vulncheck.com/advisories/libmspack-through-0-11alpha-uninitialized-memory-disclosure-via-ms-zip-decompressor-window",
      "source": "[email protected]"
    }
  ]
}