{ "schemaVersion": 1, "attribution": [ { "source": "CISA Known Exploited Vulnerabilities", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog", "licence": "US government work" }, { "source": "GitHub Advisory Database", "url": "https://github.com/advisories", "licence": "CC BY 4.0" }, { "source": "Have I Been Pwned", "url": "https://haveibeenpwned.com/", "licence": "CC BY 4.0" }, { "source": "CVE Program (CVE records)", "url": "https://www.cve.org/Legal/TermsOfUse", "licence": "CVE Terms of Use", "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.", "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy." }, { "source": "FIRST EPSS", "url": "https://www.first.org/epss/", "licence": "free to use; FIRST requests attribution" } ], "record": { "id": "CVE-2025-39985", "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2025-39985", "idYear": 2025, "status": "PUBLISHED", "publishedAt": "2025-10-15T07:56:04.439Z", "updatedAt": "2026-08-05T12:06:52.589Z", "importedAt": "2026-10-24T01:57:34.152Z", "snapshot": { "id": "cve_2026-10-24_midnight_baseline", "at": "2026-10-24T00:00:00.000Z", "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z" }, "facts": { "title": "can: mcba_usb: populate ndo_change_mtu() to prevent buffer overflow", "summary": "In the Linux kernel, the following vulnerability has been resolved:\n\ncan: mcba_usb: populate ndo_change_mtu() to prevent buffer overflow\n\nSending an PF_PACKET allows to bypass the CAN framework logic and to\ndirectly reach the xmit() function of a CAN driver. The only check\nwhich is performed by the PF_PACKET framework is to make sure that\nskb->len fits the interface's MTU.\n\nUnfortunately, because the mcba_usb driver does not populate its\nnet_device_ops->ndo_change_mtu(), it is possible for an attacker to\nconfigure an invalid MTU by doing, for example:\n\n $ ip link set can0 mtu 9999\n\nAfter doing so, the attacker could open a PF_PACKET socket using the\nETH_P_CANXL protocol:\n\n\tsocket(PF_PACKET, SOCK_RAW, htons(ETH_P_CANXL))\n\nto inject a malicious CAN XL frames. For example:\n\n\tstruct canxl_frame frame = {\n\t\t.flags = 0xff,\n\t\t.len = 2048,\n\t};\n\nThe CAN drivers' xmit() function are calling can_dev_dropped_skb() to\ncheck that the skb is valid, unfortunately under above conditions, the\nmalicious packet is able to go through can_dev_dropped_skb() checks:\n\n 1. the skb->protocol is set to ETH_P_CANXL which is valid (the\n function does not check the actual device capabilities).\n\n 2. the length is a valid CAN XL length.\n\nAnd so, mcba_usb_start_xmit() receives a CAN XL frame which it is not\nable to correctly handle and will thus misinterpret it as a CAN frame.\n\nThis can result in a buffer overflow. The driver will consume cf->len\nas-is with no further checks on these lines:\n\n\tusb_msg.dlc = cf->len;\n\n\tmemcpy(usb_msg.data, cf->data, usb_msg.dlc);\n\nHere, cf->len corresponds to the flags field of the CAN XL frame. In\nour previous example, we set canxl_frame->flags to 0xff. Because the\nmaximum expected length is 8, a buffer overflow of 247 bytes occurs!\n\nPopulate net_device_ops->ndo_change_mtu() to ensure that the\ninterface's MTU can not be set to anything bigger than CAN_MTU. By\nfixing the root cause, this prevents the buffer overflow.", "affected": [ { "vendor": "Linux", "product": "Linux", "defaultStatus": "unaffected", "versions": [ { "version": "51f3baad7de943780ce0c17bd7975df567dd6e14", "status": "affected", "versionType": "git", "lessThan": "0fa9303c4b9493727e0d3a6ac3729300e3013930" }, { "version": "51f3baad7de943780ce0c17bd7975df567dd6e14", "status": "affected", "versionType": "git", "lessThan": "37aed407496bf6de8910e588edb04d2435fa7011" }, { "version": "51f3baad7de943780ce0c17bd7975df567dd6e14", "status": "affected", "versionType": "git", "lessThan": "6eec67bfb25637f9b51e584cf59ddace59925bc8" }, { "version": "51f3baad7de943780ce0c17bd7975df567dd6e14", "status": "affected", "versionType": "git", "lessThan": "ca4e51359608e1f29bf1f2c33c3ddf775b6b7ed1" }, { "version": "51f3baad7de943780ce0c17bd7975df567dd6e14", "status": "affected", "versionType": "git", "lessThan": "3664ae91b26d1fd7e4cee9cde17301361f4c89d5" }, { "version": "51f3baad7de943780ce0c17bd7975df567dd6e14", "status": "affected", "versionType": "git", "lessThan": "6b9fb82df8868dbe9ffea5874b8d35f951faedbb" }, { "version": "51f3baad7de943780ce0c17bd7975df567dd6e14", "status": "affected", "versionType": "git", "lessThan": "b638c3fb0f163e69785ceddb3b434a9437878bec" }, { "version": "51f3baad7de943780ce0c17bd7975df567dd6e14", "status": "affected", "versionType": "git", "lessThan": "17c8d794527f01def0d1c8b7dc2d7b8d34fed0e6" } ] }, { "vendor": "Linux", "product": "Linux", "defaultStatus": "affected", "versions": [ { "version": "4.12", "status": "affected" }, { "version": "0", "status": "unaffected", "versionType": "semver", "lessThan": "4.12" }, { "version": "5.4.300", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.4.*" }, { "version": "5.10.245", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.10.*" }, { "version": "5.15.194", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.15.*" }, { "version": "6.1.155", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.1.*" }, { "version": "6.6.109", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.6.*" }, { "version": "6.12.50", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.12.*" }, { "version": "6.16.10", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.16.*" }, { "version": "6.17", "status": "unaffected", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*" } ] } ] } } }