{"id":"CVE-2026-93048","title":"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…","summary":"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…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= 1a31368bf92ef2a7da3ba379672c405bd2751df9 < 701c3ae7273e1adc20db5d97c42e0139b479f16b","Linux >= 1a31368bf92ef2a7da3ba379672c405bd2751df9 < 6aaab2ace3f7b55733d904e5549acf8405f03642","Linux >= 1a31368bf92ef2a7da3ba379672c405bd2751df9 < 181c1bff940e7d3e34ca485d37e3cdbfe409203c","Linux >= 1a31368bf92ef2a7da3ba379672c405bd2751df9 < a536eb57be58442b19398b2783071007ecfb1735","Linux >= 1a31368bf92ef2a7da3ba379672c405bd2751df9 < e204e5c49a012f99638633fdbd773e3c86260053","Linux >= 1a31368bf92ef2a7da3ba379672c405bd2751df9 < 398aca2f90122d5abbabff1079deaeb885fe9e40","Linux >= 1a31368bf92ef2a7da3ba379672c405bd2751df9 < c645f6dd1af2ecc70fd3578e141f2f71fa9e4eff","Linux >= 1a31368bf92ef2a7da3ba379672c405bd2751df9 < b759d5bb6265419344ee9729fd0dc07ad85719d8","Linux 3.2"],"published":"2026-09-17","updated":"2026-09-17","sourceUpdated":"2026-09-17T17:17:58.080","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-93048","references":[{"url":"https://git.kernel.org/stable/c/181c1bff940e7d3e34ca485d37e3cdbfe409203c","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/398aca2f90122d5abbabff1079deaeb885fe9e40","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/6aaab2ace3f7b55733d904e5549acf8405f03642","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/701c3ae7273e1adc20db5d97c42e0139b479f16b","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/a536eb57be58442b19398b2783071007ecfb1735","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/b759d5bb6265419344ee9729fd0dc07ad85719d8","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/c645f6dd1af2ecc70fd3578e141f2f71fa9e4eff","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/e204e5c49a012f99638633fdbd773e3c86260053","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd","cve.org"],"ingestedAt":"2026-09-17T16:21:47.772Z","epss":0.00211,"epssPercentile":0.11593,"slug":"CVE-2026-93048","body":"## Overview\n\nIn 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}