CVE-2026-119602

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.

CVSS v3 3.7 LOW

3.7^/10

CVSS v3 : LOW

Vector :

Exploitability : 2.2 / Impact : 1.4

Attack Vector NETWORK

Attack Complexity HIGH

Privileges Required NONE

User Interaction NONE

Confidentiality Impact LOW

Integrity Impact NONE

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://github.com/kyz/libmspack
https://github.com/kyz/libmspack/blob/v0.11alpha/libmspack/mspack/mszipd.c#L264-L276
https://github.com/kyz/libmspack/issues/60
https://hackmd.io/@haindpwn/libmspack-mszip-uninit-window-info-leak
https://www.vulncheck.com/advisories/libmspack-through-0-11alpha-uninitialized-memory-disclosure-via-ms-zip-decompressor-window

Configurations

No configuration.

History

30 Oct 2026, 14:16

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-10-30 14:16

Updated : 2026-10-30 16:17

NVD link : CVE-2026-119602

Mitre link : CVE-2026-119602

CVE.ORG link : CVE-2026-119602

JSON object : View

Products Affected

No product.

CWE

CWE-908

Use of Uninitialized Resource

{"id": "CVE-2026-119602", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-119602", "role": "CISA Coordinator", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "version": "2.0.3", "timestamp": "2026-10-30T15:21:16.087677Z"}}], "cvssMetricV31": [{"type": "Secondary", "source": "disclosure@vulncheck.com", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 3.7, "attackVector": "NETWORK", "baseSeverity": "LOW", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "HIGH", "availabilityImpact": "NONE", "privilegesRequired": "NONE", "confidentialityImpact": "LOW"}, "impactScore": 1.4, "exploitabilityScore": 2.2}], "cvssMetricV40": [{"type": "Secondary", "source": "disclosure@vulncheck.com", "cvssData": {"Safety": "NOT_DEFINED", "version": "4.0", "Recovery": "NOT_DEFINED", "baseScore": 6.3, "Automatable": "NOT_DEFINED", "attackVector": "NETWORK", "baseSeverity": "MEDIUM", "valueDensity": "NOT_DEFINED", "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", "exploitMaturity": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED", "userInteraction": "NONE", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "privilegesRequired": "NONE", "subIntegrityImpact": "NONE", "vulnIntegrityImpact": "NONE", "integrityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "vulnAvailabilityImpact": "NONE", "availabilityRequirement": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "subConfidentialityImpact": "NONE", "vulnConfidentialityImpact": "LOW", "confidentialityRequirement": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED"}}]}, "affected": [{"source": "disclosure@vulncheck.com", "affectedData": [{"repo": "https://github.com/kyz/libmspack", "vendor": "kyz", "product": "libmspack", "versions": [{"status": "affected", "version": "0", "versionType": "custom", "lessThanOrEqual": "0.11alpha"}], "packageURL": "pkg:github/kyz/libmspack", "defaultStatus": "unaffected"}]}], "published": "2026-10-30T14:16:48.700", "references": [{"url": "https://github.com/kyz/libmspack", "source": "disclosure@vulncheck.com"}, {"url": "https://github.com/kyz/libmspack/blob/v0.11alpha/libmspack/mspack/mszipd.c#L264-L276", "source": "disclosure@vulncheck.com"}, {"url": "https://github.com/kyz/libmspack/issues/60", "source": "disclosure@vulncheck.com"}, {"url": "https://hackmd.io/@haindpwn/libmspack-mszip-uninit-window-info-leak", "source": "disclosure@vulncheck.com"}, {"url": "https://www.vulncheck.com/advisories/libmspack-through-0-11alpha-uninitialized-memory-disclosure-via-ms-zip-decompressor-window", "source": "disclosure@vulncheck.com"}], "vulnStatus": "Deferred", "weaknesses": [{"type": "Secondary", "source": "disclosure@vulncheck.com", "description": [{"lang": "en", "value": "CWE-908"}]}], "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."}], "lastModified": "2026-10-30T16:17:49.240", "sourceIdentifier": "disclosure@vulncheck.com"}