CVE-2026-56392

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The multiplication used to calculate the allocation size can wrap around, resulting in an undersized buffer.\nWhen processing crafted input, subsequent writes exceed the allocated memory, leading to an out\u2011of\u2011bounds heap write.\n\nWhen running GNU coreutils unexpand with attacker-provided large tab stop (-t) arguments, this behavior leads to a crash and potentially achieve a heap write primitive depending on memory layout.\n\n\n\n\n\n\n\n\n\n\nThis issue has been fixed in the commit b60a159fdc5bfcf9988d3a4cb6f53abe8ad5d35d"}, {"lang": "es", "value": "GNU coreutils unexpand es vulnerable a un desbordamiento de b\u00fafer basado en mont\u00edculo debido a un desbordamiento de entero durante la asignaci\u00f3n de b\u00fafer al procesar valores grandes de tabulaci\u00f3n (-t). La multiplicaci\u00f3n utilizada para calcular el tama\u00f1o de la asignaci\u00f3n puede dar la vuelta, lo que resulta en un b\u00fafer de tama\u00f1o insuficiente.\nAl procesar entrada manipulada, las escrituras subsiguientes exceden la memoria asignada, lo que lleva a una escritura fuera de l\u00edmites en el mont\u00edculo.\n\nAl ejecutar GNU coreutils unexpand con argumentos de tabulaci\u00f3n (-t) grandes proporcionados por el atacante, este comportamiento lleva a un fallo y potencialmente logra una primitiva de escritura en el mont\u00edculo dependiendo del dise\u00f1o de la memoria.\n\nEste problema ha sido corregido en el commit b60a159fdc5bfcf9988d3a4cb6f53abe8ad5d35d"}], "id": "CVE-2026-56392", "lastModified": "2026-10-24T13:10:00.147", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 6.1, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "LOW", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "REQUIRED", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:H", "version": "3.1"}, "exploitabilityScore": 1.8, "impactScore": 4.2, "source": "nvd@nist.gov", "type": "Primary"}], "cvssMetricV40": [{"cvssData": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "attackVector": "LOCAL", "availabilityRequirement": "NOT_DEFINED", "baseScore": 1.8, "baseSeverity": "LOW", "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": "ACTIVE", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:A/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": "cvd@cert.pl", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-56392", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "role": "CISA Coordinator", "timestamp": "2026-07-24T12:32:03.340535Z", "version": "2.0.3"}}]}, "published": "2026-07-24T09:16:25.147", "references": [{"source": "cvd@cert.pl", "tags": ["Third Party Advisory"], "url": "https://cert.pl/en/posts/2026/07/CVE-2026-56391"}, {"source": "cvd@cert.pl", "tags": ["Product"], "url": "https://git.savannah.gnu.org/cgit/coreutils.git/"}, {"source": "cvd@cert.pl", "tags": ["Patch"], "url": "https://git.savannah.gnu.org/cgit/coreutils.git/commit/?id=b60a159fdc5bfcf9988d3a4cb6f53abe8ad5d35d"}], "sourceIdentifier": "cvd@cert.pl", "vulnStatus": "Analyzed", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-122"}], "source": "cvd@cert.pl", "type": "Secondary"}]}

{"bugzilla": {"description": "coreutils: GNU coreutils unexpand: Denial of Service via crafted tab stop values", "id": "2506694", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2506694"}, "csaw": false, "cvss3": {"cvss3_base_score": "4.4", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:L", "status": "draft"}, "cwe": "CWE-787", "details": ["A flaw was found in GNU coreutils, specifically in the `unexpand` utility. This vulnerability, a heap-based buffer overflow, occurs due to an integer overflow when `unexpand` processes unusually large tab stop values provided by a local attacker. This can lead to an undersized memory buffer, allowing subsequent operations to write beyond its boundaries. Successful exploitation can cause the `unexpand` utility to crash, potentially resulting in a denial of service or enabling further memory manipulation."], "mitigation": {"lang": "en:us", "value": "Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability."}, "name": "CVE-2026-56392", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Fix deferred", "package_name": "coreutils", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Out of support scope", "package_name": "coreutils", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Out of support scope", "package_name": "coreutils", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Fix deferred", "package_name": "coreutils", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "coreutils", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/a:redhat:hummingbird:1", "fix_state": "Affected", "package_name": "coreutils", "product_name": "Red Hat Hardened Images"}, {"cpe": "cpe:/a:redhat:openshift:4", "fix_state": "Under investigation", "package_name": "rhcos", "product_name": "Red Hat OpenShift Container Platform 4"}], "public_date": "2026-07-24T07:44:54Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-56392\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-56392\nhttps://cert.pl/en/posts/2026/07/CVE-2026-56391\nhttps://git.savannah.gnu.org/cgit/coreutils.git/\nhttps://git.savannah.gnu.org/cgit/coreutils.git/commit/?id=b60a159fdc5bfcf9988d3a4cb6f53abe8ad5d35d"], "statement": "A Moderate impact heap-based buffer overflow flaw was found in the `unexpand` utility of GNU coreutils. This vulnerability arises from an integer overflow when processing unusually large tab stop values, leading to an undersized buffer. A local attacker could exploit this by providing crafted input, causing the utility to crash and potentially leading to a denial of service or arbitrary memory manipulation.", "threat_severity": "Moderate"}

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