{"id":"CVE-2026-46124","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nisofs: validate block number from NFS file handle in isofs_export_iget\n\nisofs_fh_to_dentry() and isofs_fh_to_parent() pass an attacker-\ncontrolled block number (ifid->b…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nisofs: validate block number from NFS file handle in isofs_export_iget\n\nisofs_fh_to_dentry() and isofs_fh_to_parent() pass an attacker-\ncontrolled block number (ifid->b…","severity":"high","cvss":7.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","vendor":"linux","product":"linux_kernel","affected":["linux_kernel >= 5.4.293, < 5.5","linux_kernel >= 5.10.237, < 5.10.258","linux_kernel >= 5.15.181, < 5.15.209","linux_kernel >= 6.1.135, < 6.1.175","linux_kernel >= 6.6.88, < 6.6.140","linux_kernel >= 6.12.25, < 6.12.88","linux_kernel >= 6.14.4, < 6.15","linux_kernel >= 6.15.1, < 6.18.30","linux_kernel >= 6.19, < 7.0.7","linux_kernel = 6.15","linux_kernel = 7.1"],"patched":["linux_kernel 7.0.7"],"published":"2026-05-28","updated":"2026-10-15","sourceUpdated":"2026-10-15T02:19:44.953","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-46124","references":[{"url":"https://git.kernel.org/stable/c/0a1af74ae2177bda3aee0837a0546309aa539d0d","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/24376458138387fb251e782e624c7776e9826796","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/31dbb4ba0f719ae7774e4c0c95172c9bf81692f5","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/4c721a1d9b3c4fcaf59cc9b2281e3ec5a043e1a6","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/908a76f0b1038035e6ebb4f2293ce079f92e0a02","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/afbafeddf23db13fe2edb2d5c0bf4bbb13d7881b","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/bb0988ed4f2e26d59bbb58f644cb3a55b7521e21","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/ee0024f5a7e3c73aa253869fae9650ae054093ca","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-784472.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"}],"tags":["nvd","cve.org"],"epss":0.00579,"epssPercentile":0.46362,"ingestedAt":"2026-10-15T03:30:12.889Z","slug":"CVE-2026-46124","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nisofs: validate block number from NFS file handle in isofs_export_iget\n\nisofs_fh_to_dentry() and isofs_fh_to_parent() pass an attacker-\ncontrolled block number (ifid->block or ifid->parent_block) from\nthe NFS file handle to isofs_export_iget(), which only rejects\nblock == 0 before calling isofs_iget() and ultimately sb_bread().\nA crafted file handle with fh_len sufficient to pass the check\nadded by commit 0405d4b63d08 (\"isofs: Prevent the use of too small\nfid\") can still drive the server to read any in-range block on the\nbacking device as if it were an iso_directory_record.  That earlier\nfix was assigned CVE-2025-37780.\n\nsb_bread() on an out-of-range block returns NULL cleanly via the\nEIO path, so there is no memory-safety violation.  For in-range\nreads of adjacent-partition data on the same block device, the\nunrelated bytes end up in iso_inode_info fields that reach the NFS\nclient as dentry metadata.  The deployment surface (isofs exported\nover NFS from loop-mounted images) is narrow and requires an\nauthenticated NFS peer, but the malformed-file-handle class is\nreportable as hardening next to the existing CVE-2025-37780 fix.\n\nReject block >= ISOFS_SB(sb)->s_nzones in isofs_export_iget() so\nthe check covers both isofs_fh_to_dentry() and isofs_fh_to_parent()\ncall sites with a single line.\n\n## Affected\n\n- `linux_kernel >= 5.4.293, < 5.5`\n- `linux_kernel >= 5.10.237, < 5.10.258`\n- `linux_kernel >= 5.15.181, < 5.15.209`\n- `linux_kernel >= 6.1.135, < 6.1.175`\n- `linux_kernel >= 6.6.88, < 6.6.140`\n- `linux_kernel >= 6.12.25, < 6.12.88`\n- `linux_kernel >= 6.14.4, < 6.15`\n- `linux_kernel >= 6.15.1, < 6.18.30`\n- `linux_kernel >= 6.19, < 7.0.7`\n- `linux_kernel = 6.15`\n- `linux_kernel = 7.1`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `linux_kernel 7.0.7`","depth":"twilight","depthScore":41,"depthScoreParts":{"impact":41.3,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}