{ "schemaVersion": 1, "attribution": [ { "source": "CISA Known Exploited Vulnerabilities", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog", "licence": "US government work" }, { "source": "GitHub Advisory Database", "url": "https://github.com/advisories", "licence": "CC BY 4.0" }, { "source": "Have I Been Pwned", "url": "https://haveibeenpwned.com/", "licence": "CC BY 4.0" }, { "source": "CVE Program (CVE records)", "url": "https://www.cve.org/Legal/TermsOfUse", "licence": "CVE Terms of Use", "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.", "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy." }, { "source": "FIRST EPSS", "url": "https://www.first.org/epss/", "licence": "free to use; FIRST requests attribution" } ], "record": { "id": "CVE-2025-39775", "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2025-39775", "idYear": 2025, "status": "PUBLISHED", "publishedAt": "2025-09-11T16:56:28.230Z", "updatedAt": "2026-10-21T12:37:20.574Z", "importedAt": "2026-10-24T01:57:34.152Z", "snapshot": { "id": "cve_2026-10-24_midnight_baseline", "at": "2026-10-24T00:00:00.000Z", "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z" }, "facts": { "title": "mm/mremap: fix WARN with uffd that has remap events disabled", "summary": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/mremap: fix WARN with uffd that has remap events disabled\n\nRegistering userfaultd on a VMA that spans at least one PMD and then\nmremap()'ing that VMA can trigger a WARN when recovering from a failed\npage table move due to a page table allocation error.\n\nThe code ends up doing the right thing (recurse, avoiding moving actual\npage tables), but triggering that WARN is unpleasant:\n\nWARNING: CPU: 2 PID: 6133 at mm/mremap.c:357 move_normal_pmd mm/mremap.c:357 [inline]\nWARNING: CPU: 2 PID: 6133 at mm/mremap.c:357 move_pgt_entry mm/mremap.c:595 [inline]\nWARNING: CPU: 2 PID: 6133 at mm/mremap.c:357 move_page_tables+0x3832/0x44a0 mm/mremap.c:852\nModules linked in:\nCPU: 2 UID: 0 PID: 6133 Comm: syz.0.19 Not tainted 6.17.0-rc1-syzkaller-00004-g53e760d89498 #0 PREEMPT(full)\nHardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014\nRIP: 0010:move_normal_pmd mm/mremap.c:357 [inline]\nRIP: 0010:move_pgt_entry mm/mremap.c:595 [inline]\nRIP: 0010:move_page_tables+0x3832/0x44a0 mm/mremap.c:852\nCode: ...\nRSP: 0018:ffffc900037a76d8 EFLAGS: 00010293\nRAX: 0000000000000000 RBX: 0000000032930007 RCX: ffffffff820c6645\nRDX: ffff88802e56a440 RSI: ffffffff820c7201 RDI: 0000000000000007\nRBP: ffff888037728fc0 R08: 0000000000000007 R09: 0000000000000000\nR10: 0000000032930007 R11: 0000000000000000 R12: 0000000000000000\nR13: ffffc900037a79a8 R14: 0000000000000001 R15: dffffc0000000000\nFS: 000055556316a500(0000) GS:ffff8880d68bc000(0000) knlGS:0000000000000000\nCS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033\nCR2: 0000001b30863fff CR3: 0000000050171000 CR4: 0000000000352ef0\nCall Trace:\n \n copy_vma_and_data+0x468/0x790 mm/mremap.c:1215\n move_vma+0x548/0x1780 mm/mremap.c:1282\n mremap_to+0x1b7/0x450 mm/mremap.c:1406\n do_mremap+0xfad/0x1f80 mm/mremap.c:1921\n __do_sys_mremap+0x119/0x170 mm/mremap.c:1977\n do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]\n do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\nRIP: 0033:0x7f00d0b8ebe9\nCode: ...\nRSP: 002b:00007ffe5ea5ee98 EFLAGS: 00000246 ORIG_RAX: 0000000000000019\nRAX: ffffffffffffffda RBX: 00007f00d0db5fa0 RCX: 00007f00d0b8ebe9\nRDX: 0000000000400000 RSI: 0000000000c00000 RDI: 0000200000000000\nRBP: 00007ffe5ea5eef0 R08: 0000200000c00000 R09: 0000000000000000\nR10: 0000000000000003 R11: 0000000000000246 R12: 0000000000000002\nR13: 00007f00d0db5fa0 R14: 00007f00d0db5fa0 R15: 0000000000000005\n \n\nThe underlying issue is that we recurse during the original page table\nmove, but not during the recovery move.\n\nFix it by checking for both VMAs and performing the check before the\npmd_none() sanity check.\n\nAdd a new helper where we perform+document that check for the PMD and PUD\nlevel.\n\nThanks to Harry for bisecting.", "affected": [ { "vendor": "Linux", "product": "Linux", "defaultStatus": "unaffected", "versions": [ { "version": "310ac886d68de661c3a334198d8604b722d7fdf8", "status": "affected", "versionType": "git", "lessThan": "1c15b4cd3a97aea013bdb18d9a55ca0384fbb8d4" }, { "version": "0cef0bb836e3cfe00f08f9606c72abd72fe78ca3", "status": "affected", "versionType": "git", "lessThan": "d70ca21f7bff162a5afae1ddd6f4107adf05ae23" }, { "version": "0cef0bb836e3cfe00f08f9606c72abd72fe78ca3", "status": "affected", "versionType": "git", "lessThan": "772e5b4a5e8360743645b9a466842d16092c4f94" }, { "version": "8e2f6ba256dd1e590addc48e6e9577bf39c482f2", "status": "affected", "versionType": "git" }, { "version": "6.12.11", "status": "affected", "versionType": "semver", "lessThan": "6.12.114" }, { "version": "6.6.160", "status": "affected", "versionType": "semver", "lessThan": "6.7" } ] }, { "vendor": "Linux", "product": "Linux", "defaultStatus": "affected", "versions": [ { "version": "6.13", "status": "affected" }, { "version": "0", "status": "unaffected", "versionType": "semver", "lessThan": "6.13" }, { "version": "6.12.114", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.12.*" }, { "version": "6.16.4", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.16.*" }, { "version": "6.17", "status": "unaffected", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*" } ] } ] } } }