{"cve":"CVE-2026-23375","nvd":{"published":"2026-03-25T11:16:37.230","modified":"2026-06-17T10:21:27.453","status":"Analyzed","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm: thp: deny THP for files on anonymous inodes\n\nfile_thp_enabled() incorrectly allows THP for files on anonymous inodes\n(e.g. guest_memfd and secretmem). These files are created via\nalloc_file_pseudo(), which does not call get_write_access() and leaves\ninode->i_writecount at 0. Combined with S_ISREG(inode->i_mode) being\ntrue, they appear as read-only regular files when\nCONFIG_READ_ONLY_THP_FOR_FS is enabled, making them eligible for THP\ncollapse.\n\nAnonymous inodes can never pass the inode_is_open_for_write() check\nsince their i_writecount is never incremented through the normal VFS\nopen path. The right thing to do is to exclude them from THP eligibility\naltogether, since CONFIG_READ_ONLY_THP_FOR_FS was designed for real\nfilesystem files (e.g. shared libraries), not for pseudo-filesystem\ninodes.\n\nFor guest_memfd, this allows khugepaged and MADV_COLLAPSE to create\nlarge folios in the page cache via the collapse path, but the\nguest_memfd fault handler does not support large folios. This triggers\nWARN_ON_ONCE(folio_test_large(folio)) in kvm_gmem_fault_user_mapping().\n\nFor secretmem, collapse_file() tries to copy page contents through the\ndirect map, but secretmem pages are removed from the direct map. This\ncan result in a kernel crash:\n\n    BUG: unable to handle page fault for address: ffff88810284d000\n    RIP: 0010:memcpy_orig+0x16/0x130\n    Call Trace:\n     collapse_file\n     hpage_collapse_scan_file\n     madvise_collapse\n\nSecretmem is not affected by the crash on upstream as the memory failure\nrecovery handles the failed copy gracefully, but it still triggers\nconfusing false memory failure reports:\n\n    Memory failure: 0x106d96f: recovery action for clean unevictable\n    LRU page: Recovered\n\nCheck IS_ANON_FILE(inode) in file_thp_enabled() to deny THP for all\nanonymous inode files.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","score":5.5},"cwes":["CWE-617"],"references":["https://git.kernel.org/stable/c/0524ee56af2c9bfbad152a810f1ca95de8ca00d7","https://git.kernel.org/stable/c/08de46a75f91a6661bc1ce0a93614f4bc313c581","https://git.kernel.org/stable/c/dd085fe9a8ebfc5d10314c60452db38d2b75e609","https://git.kernel.org/stable/c/f6fa05f0dddd387417d0c28281ddb951582514d6"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T22:28:18.033120106+00:00"},"epss":{"cve":"CVE-2026-23375","score":0.00123,"percentile":0.0207,"date":"2026-10-31"},"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."]}