{"cve":"CVE-2026-97926","nvd":{"published":"2026-09-25T11:17:19.833","modified":"2026-10-19T10:17:43.410","status":"Received","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nufs: validate cylinder group metadata before caching it\n\nufs_read_cylinder() copies the cylinder group index and the rotor\npositions straight from the on-disk group and caches them without any\ncheck:\n\n\tucpi->c_cgx    = fs32_to_cpu(sb, ucg->cg_cgx);\n\tucpi->c_rotor  = fs32_to_cpu(sb, ucg->cg_rotor);\n\tucpi->c_frotor = fs32_to_cpu(sb, ucg->cg_frotor);\n\tucpi->c_irotor = fs32_to_cpu(sb, ucg->cg_irotor);\n\nThey are then used as indices during allocation and free:\n\n  - c_cgx indexes the cylinder summary array as\n    UFS_SB(sb)->fs_cs(ucpi->c_cgx), so a value past s_ncg writes a 32\n    bit count outside the s_csp allocation.\n\n  - c_frotor becomes a bitmap scan start, start = c_frotor >> 3, and\n    then length = ((s_fpg + 7) >> 3) - start. A start beyond the block\n    bitmap wraps the unsigned length to a huge value, so ubh_scanc()\n    walks far past the cylinder group buffers. c_irotor drives the\n    inode bitmap the same way.\n\nA crafted image can set any of these freely, turning an ordinary\nallocation into an out of bounds access.\n\nReject a cylinder group whose recorded index does not match the group\nbeing read, or whose rotors fall outside the group, before the metadata\nis cached. Valid filesystems keep cg_cgx equal to the group number and\nthe rotors within the group, so only malformed images are rejected.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H","score":7.0},"cwes":[],"references":["https://git.kernel.org/stable/c/58c0c414b2b8d099d33da494a354fa836ca6c10b","https://git.kernel.org/stable/c/5902a95066883cf96fa15b2680694fc5dd0c7d11","https://git.kernel.org/stable/c/87b12dc360a002eb2d498aa4f01e84347019612d","https://git.kernel.org/stable/c/88cccb6beba136b73f0caf80e59457e1b3c0ca1e","https://git.kernel.org/stable/c/abde9eb33106850dfa367ad3965d3588bb8558d5"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:56:02.509636177+00:00"},"epss":{"cve":"CVE-2026-97926","score":0.00154,"percentile":0.04441,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}