{"id":"CVE-2026-93048","revision":"4b861b92353843cfa3f59e3e0678f3ac","records":[{"revision":"4b861b92353843cfa3f59e3e0678f3ac","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-93048","aliases":[],"title":"mtd: part: reject MTDPART_OFS_RETAIN in mtd_add_partition()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nmtd: part: reject MTDPART_OFS_RETAIN in mtd_add_partition()\n\nmtd_add_partition() does not reject the special offset value\nMTDPART_OFS_RETAIN (-3), which leads to a WARN_ON in\nadd_mtd_device() when called through the BLKPG ioctl on NAND\ndevices. The RETAIN value depends on cur_offset being the end of\nthe previous partition, but in the dynamic partition path\ncur_offset equals the offset argument itself, causing undefined\nbehavior.\n\nCommit 5daa7b21496a (\"mtd: prepare partition add and del functions\nfor ioctl requests\") introduced mtd_add_partition() and correctly\nrejected MTDPART_OFS_APPEND (-1) and MTDPART_OFS_NXTBLK (-2),\nsince those special offsets rely on cur_offset tracking the\nprevious partition's end. However, commit 1a31368bf92e (\"mtd: add a flags\nfor partitions which should just leave smth. after them\")\nlater added MTDPART_OFS_RETAIN (-3) for the static\npartition table path without updating mtd_add_partition() to\nalso reject this value.\n\nWith offset=-3 passed via BLKPG, the RETAIN size calculation in\nallocate_partition() underflows (parent_size - 0xFFFFFFFFFFFFFFFD\n= parent_size + 3). If the underflow result does not appear to\nleave enough space, allocate_partition() jumps to out_register via\ngoto, skipping erasesize initialization. This results in\nerasesize=0, which triggers:\n\nWARN_ON((!mtd->erasesize || !master->_erase) &&\n\t\t!(mtd->flags & MTD_NO_ERASE))\n\nin add_mtd_device(). If the underflow result appears to leave\nenough space, a bogus partition size is calculated, but the\n\"out of reach\" sanity check catches the invalid offset and\ncreates a disabled empty partition (offset=0, size=0) instead\nof returning an error.\n\nFix this by adding MTDPART_OFS_RETAIN to the rejection list in\nmtd_add_partition(), consistent with the existing handling of\nAPPEND and NXTBLK.","state":0,"publishedAt":"2026-09-17T16:10:39.008+00:00","modifiedAt":"2026-10-19T09:04:43.363+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"drivers/mtd/mtdpart.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"1a31368bf92ef2a7da3ba379672c405bd2751df9\",\n                            \"lessThan\": \"701c3ae7273e1adc20db5d97c42e0139b479f16b\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"1a31368bf92ef2a7da3ba379672c405bd2751df9\",\n                            \"lessThan\": \"6aaab2ace3f7b55733d904e5549acf8405f03642\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"1a31368bf92ef2a7da3ba379672c405bd2751df9\",\n                            \"lessThan\": \"181c1bff940e7d3e34ca485d37e3cdbfe409203c\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"1a31368bf92ef2a7da3ba379672c405bd2751df9\",\n                            \"lessThan\": \"a536eb57be58442b19398b2783071007ecfb1735\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"1a31368bf92ef2a7da3ba379672c405bd2751df9\",\n                            \"lessThan\": \"e204e5c49a012f99638633fdbd773e3c86260053\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"1a31368bf92ef2a7da3ba379672c405bd2751df9\",\n                            \"lessThan\": \"398aca2f90122d5abbabff1079deaeb885fe9e40\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"1a31368bf92ef2a7da3ba379672c405bd2751df9\",\n                            \"lessThan\": \"c645f6dd1af2ecc70fd3578e141f2f71fa9e4eff\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"1a31368bf92ef2a7da3ba379672c405bd2751df9\",\n                            \"lessThan\": \"b759d5bb6265419344ee9729fd0dc07ad85719d8\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        }\n                    ]\n                }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"affected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"drivers/mtd/mtdpart.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"3.2\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"3.2\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.10.270\",\n                            \"lessThanOrEqual\": \"5.10.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.15.221\",\n                            \"lessThanOrEqual\": \"5.15.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.1.188\",\n                            \"lessThanOrEqual\": \"6.1.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.6.157\",\n                            \"lessThanOrEqual\": \"6.6.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.12.110\",\n                            \"lessThanOrEqual\": \"6.12.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.52\",\n                            \"lessThanOrEqual\": \"6.18.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.2.6\",\n                            \"lessThanOrEqual\": \"7.2.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.3\",\n                            \"lessThanOrEqual\": \"*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"original_commit_for_fix\"\n                        }\n                    ]\n                }"}],"metrics":[],"references":["https://git.kernel.org/stable/c/701c3ae7273e1adc20db5d97c42e0139b479f16b","https://git.kernel.org/stable/c/6aaab2ace3f7b55733d904e5549acf8405f03642","https://git.kernel.org/stable/c/181c1bff940e7d3e34ca485d37e3cdbfe409203c","https://git.kernel.org/stable/c/a536eb57be58442b19398b2783071007ecfb1735","https://git.kernel.org/stable/c/e204e5c49a012f99638633fdbd773e3c86260053","https://git.kernel.org/stable/c/398aca2f90122d5abbabff1079deaeb885fe9e40","https://git.kernel.org/stable/c/c645f6dd1af2ecc70fd3578e141f2f71fa9e4eff","https://git.kernel.org/stable/c/b759d5bb6265419344ee9729fd0dc07ad85719d8"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-93048","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-93048","identifiers":["CVE-2026-93048"]},"retained":false,"historicalAffected":[]}],"coverage":[]}