CVE-2025-70100

A divide-by-zero vulnerability in the ext4_block_set_lb_size function in src/ext4_blockdev.c of the lwext4 1.0.0 library allows attackers to cause a denial of service by providing a malformed ext4 filesystem image that results in a zero logical block size. The vulnerability is triggered during mount or image processing and leads to a Floating-Point Exception (FPE) under sanitizers or a runtime crash in standard builds due to missing validation of lb_size.

CVSS v3 5.5 MEDIUM

5.5^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 1.8 / Impact : 3.6

Attack Vector LOCAL

Attack Complexity LOW

Privileges Required NONE

User Interaction REQUIRED

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://github.com/gkostka/lwext4/issues/90	Exploit Issue Tracking Patch
https://github.com/sigdevel/pocs/blob/main/res/lwext4/2/sig8_2_lwext4_ext4_blockdev_c_127	Exploit
https://infosec.exchange/@sigdevel/116668952003072580	Exploit Patch Third Party Advisory
http://www.openwall.com/lists/oss-security/2026/06/29/5
https://github.com/gkostka/lwext4/issues/90	Exploit Issue Tracking Patch

Configurations

Configuration 1 (hide)

cpe:2.3:a:gkostka:lwext4:1.0.0:*:*:*:*:*:*:*

History

No history.

Information

Published : 2026-06-03 14:16

Updated : 2026-07-22 19:10

NVD link : CVE-2025-70100

Mitre link : CVE-2025-70100

CVE.ORG link : CVE-2025-70100

JSON object : View

Products Affected

gkostka

lwext4

CWE

CWE-369

Divide By Zero

{"id": "CVE-2025-70100", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2025-70100", "role": "CISA Coordinator", "options": [{"exploitation": "poc"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "version": "2.0.3", "timestamp": "2026-06-03T17:33:43.633264Z"}}], "cvssMetricV31": [{"type": "Secondary", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 5.5, "attackVector": "LOCAL", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H", "integrityImpact": "NONE", "userInteraction": "REQUIRED", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "NONE", "confidentialityImpact": "NONE"}, "impactScore": 3.6, "exploitabilityScore": 1.8}]}, "affected": [{"source": "cve@mitre.org", "affectedData": [{"vendor": "n/a", "product": "n/a", "versions": [{"status": "affected", "version": "n/a"}]}]}], "published": "2026-06-03T14:16:31.217", "references": [{"url": "https://github.com/gkostka/lwext4/issues/90", "tags": ["Exploit", "Issue Tracking", "Patch"], "source": "cve@mitre.org"}, {"url": "https://github.com/sigdevel/pocs/blob/main/res/lwext4/2/sig8_2_lwext4_ext4_blockdev_c_127", "tags": ["Exploit"], "source": "cve@mitre.org"}, {"url": "https://infosec.exchange/@sigdevel/116668952003072580", "tags": ["Exploit", "Patch", "Third Party Advisory"], "source": "cve@mitre.org"}, {"url": "http://www.openwall.com/lists/oss-security/2026/06/29/5", "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "https://github.com/gkostka/lwext4/issues/90", "tags": ["Exploit", "Issue Tracking", "Patch"], "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"}], "vulnStatus": "Modified", "weaknesses": [{"type": "Secondary", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "description": [{"lang": "en", "value": "CWE-369"}]}], "descriptions": [{"lang": "en", "value": "A divide-by-zero vulnerability in the ext4_block_set_lb_size function in src/ext4_blockdev.c of the lwext4 1.0.0 library allows attackers to cause a denial of service by providing a malformed ext4 filesystem image that results in a zero logical block size. The vulnerability is triggered during mount or image processing and leads to a Floating-Point Exception (FPE) under sanitizers or a runtime crash in standard builds due to missing validation of lb_size."}, {"lang": "es", "value": "Una vulnerabilidad de divisi\u00f3n por cero en la funci\u00f3n ext4_block_set_lb_size en src/ext4_blockdev.c de la biblioteca lwext4 1.0.0 permite a los atacantes causar una denegaci\u00f3n de servicio al proporcionar una imagen de sistema de archivos ext4 malformada que resulta en un tama\u00f1o de bloque l\u00f3gico cero. La vulnerabilidad se activa durante el montaje o el procesamiento de la imagen y conduce a una Excepci\u00f3n de Punto Flotante (FPE) bajo sanitizadores o un fallo en tiempo de ejecuci\u00f3n en compilaciones est\u00e1ndar debido a la falta de validaci\u00f3n de lb_size."}], "lastModified": "2026-07-22T19:10:00.120", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:gkostka:lwext4:1.0.0:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "70BC7F76-4450-4CC3-8C76-64CBB6EC4740"}], "operator": "OR"}]}], "sourceIdentifier": "cve@mitre.org"}