{"api_version":"1","generated_at":"2026-10-23T23:40:45+00:00","cve":"CVE-2025-40237","urls":{"html":"https://cve.report/CVE-2025-40237","api":"https://cve.report/api/cve/CVE-2025-40237.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2025-40237","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2025-40237"},"summary":{"title":"fs/notify: call exportfs_encode_fid with s_umount","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nfs/notify: call exportfs_encode_fid with s_umount\n\nCalling intotify_show_fdinfo() on fd watching an overlayfs inode, while\nthe overlayfs is being unmounted, can lead to dereferencing NULL ptr.\n\nThis issue was found by syzkaller.\n\nRace Condition Diagram:\n\nThread 1                           Thread 2\n--------                           --------\n\ngeneric_shutdown_super()\n shrink_dcache_for_umount\n  sb->s_root = NULL\n\n                    |\n                    |             vfs_read()\n                    |              inotify_fdinfo()\n                    |               * inode get from mark *\n                    |               show_mark_fhandle(m, inode)\n                    |                exportfs_encode_fid(inode, ..)\n                    |                 ovl_encode_fh(inode, ..)\n                    |                  ovl_check_encode_origin(inode)\n                    |                   * deref i_sb->s_root *\n                    |\n                    |\n                    v\n fsnotify_sb_delete(sb)\n\nWhich then leads to:\n\n[   32.133461] Oops: general protection fault, probably for non-canonical address 0xdffffc0000000006: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN NOPTI\n[   32.134438] KASAN: null-ptr-deref in range [0x0000000000000030-0x0000000000000037]\n[   32.135032] CPU: 1 UID: 0 PID: 4468 Comm: systemd-coredum Not tainted 6.17.0-rc6 #22 PREEMPT(none)\n\n<snip registers, unreliable trace>\n\n[   32.143353] Call Trace:\n[   32.143732]  ovl_encode_fh+0xd5/0x170\n[   32.144031]  exportfs_encode_inode_fh+0x12f/0x300\n[   32.144425]  show_mark_fhandle+0xbe/0x1f0\n[   32.145805]  inotify_fdinfo+0x226/0x2d0\n[   32.146442]  inotify_show_fdinfo+0x1c5/0x350\n[   32.147168]  seq_show+0x530/0x6f0\n[   32.147449]  seq_read_iter+0x503/0x12a0\n[   32.148419]  seq_read+0x31f/0x410\n[   32.150714]  vfs_read+0x1f0/0x9e0\n[   32.152297]  ksys_read+0x125/0x240\n\nIOW ovl_check_encode_origin derefs inode->i_sb->s_root, after it was set\nto NULL in the unmount path.\n\nFix it by protecting calling exportfs_encode_fid() from\nshow_mark_fhandle() with s_umount lock.\n\nThis form of fix was suggested by Amir in [1].\n\n[1]: https://lore.kernel.org/all/CAOQ4uxhbDwhb+2Brs1UdkoF0a3NSdBAOQPNfEHjahrgoKJpLEw@mail.gmail.com/","state":"PUBLISHED","assigner":"Linux","published_at":"2025-12-04 16:16:16","updated_at":"2026-10-19 21:10:00"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/950b604384fd75d62e860bec7135b2b62eb4d508","name":"https://git.kernel.org/stable/c/950b604384fd75d62e860bec7135b2b62eb4d508","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/3f307a9f7a7a2822e38ac451b73e2244e7279496","name":"https://git.kernel.org/stable/c/3f307a9f7a7a2822e38ac451b73e2244e7279496","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/d1894bc542becb0fda61e7e513b09523cab44030","name":"https://git.kernel.org/stable/c/d1894bc542becb0fda61e7e513b09523cab44030","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/a7c4bb43bfdc2b9f06ee9d036028ed13a83df42a","name":"https://git.kernel.org/stable/c/a7c4bb43bfdc2b9f06ee9d036028ed13a83df42a","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/bc1c6b803e14ea2b8f7e33b7164013f666ceb656","name":"https://git.kernel.org/stable/c/bc1c6b803e14ea2b8f7e33b7164013f666ceb656","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2025-40237","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2025-40237","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected a1a541fbfa7e97c1100144db34b57553d7164ce5 950b604384fd75d62e860bec7135b2b62eb4d508 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected f0c0ac84de17c37e6e84da65fb920f91dada55ad bc1c6b803e14ea2b8f7e33b7164013f666ceb656 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 3c7c90274ae339e1ad443c9be1c67a20b80b9c76 3f307a9f7a7a2822e38ac451b73e2244e7279496 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected c45beebfde34aa71afbc48b2c54cdda623515037 d1894bc542becb0fda61e7e513b09523cab44030 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected c45beebfde34aa71afbc48b2c54cdda623515037 a7c4bb43bfdc2b9f06ee9d036028ed13a83df42a git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.6.72 6.6.73 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.6.74 6.6.115 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.12.10 6.12.56 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.13","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.13 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.73 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.115 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.56 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.17.6 6.17.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2025","cve_id":"40237","cve":"CVE-2025-40237","epss":"0.002010000","percentile":"0.094100000","score_date":"2026-10-19","updated_at":"2026-10-20 00:13:48"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["fs/notify/fdinfo.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"950b604384fd75d62e860bec7135b2b62eb4d508","status":"affected","version":"a1a541fbfa7e97c1100144db34b57553d7164ce5","versionType":"git"},{"lessThan":"bc1c6b803e14ea2b8f7e33b7164013f666ceb656","status":"affected","version":"f0c0ac84de17c37e6e84da65fb920f91dada55ad","versionType":"git"},{"lessThan":"3f307a9f7a7a2822e38ac451b73e2244e7279496","status":"affected","version":"3c7c90274ae339e1ad443c9be1c67a20b80b9c76","versionType":"git"},{"lessThan":"d1894bc542becb0fda61e7e513b09523cab44030","status":"affected","version":"c45beebfde34aa71afbc48b2c54cdda623515037","versionType":"git"},{"lessThan":"a7c4bb43bfdc2b9f06ee9d036028ed13a83df42a","status":"affected","version":"c45beebfde34aa71afbc48b2c54cdda623515037","versionType":"git"},{"lessThan":"6.6.73","status":"affected","version":"6.6.72","versionType":"semver"},{"lessThan":"6.6.115","status":"affected","version":"6.6.74","versionType":"semver"},{"lessThan":"6.12.56","status":"affected","version":"6.12.10","versionType":"semver"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["fs/notify/fdinfo.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"6.13"},{"lessThan":"6.13","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.73","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.115","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.56","versionType":"semver"},{"lessThanOrEqual":"6.17.*","status":"unaffected","version":"6.17.6","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"6.18","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.73","versionStartIncluding":"6.6.72","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.115","versionStartIncluding":"6.6.74","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.56","versionStartIncluding":"6.12.10","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.17.6","versionStartIncluding":"6.13","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18","versionStartIncluding":"6.13","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nfs/notify: call exportfs_encode_fid with s_umount\n\nCalling intotify_show_fdinfo() on fd watching an overlayfs inode, while\nthe overlayfs is being unmounted, can lead to dereferencing NULL ptr.\n\nThis issue was found by syzkaller.\n\nRace Condition Diagram:\n\nThread 1                           Thread 2\n--------                           --------\n\ngeneric_shutdown_super()\n shrink_dcache_for_umount\n  sb->s_root = NULL\n\n                    |\n                    |             vfs_read()\n                    |              inotify_fdinfo()\n                    |               * inode get from mark *\n                    |               show_mark_fhandle(m, inode)\n                    |                exportfs_encode_fid(inode, ..)\n                    |                 ovl_encode_fh(inode, ..)\n                    |                  ovl_check_encode_origin(inode)\n                    |                   * deref i_sb->s_root *\n                    |\n                    |\n                    v\n fsnotify_sb_delete(sb)\n\nWhich then leads to:\n\n[   32.133461] Oops: general protection fault, probably for non-canonical address 0xdffffc0000000006: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN NOPTI\n[   32.134438] KASAN: null-ptr-deref in range [0x0000000000000030-0x0000000000000037]\n[   32.135032] CPU: 1 UID: 0 PID: 4468 Comm: systemd-coredum Not tainted 6.17.0-rc6 #22 PREEMPT(none)\n\n<snip registers, unreliable trace>\n\n[   32.143353] Call Trace:\n[   32.143732]  ovl_encode_fh+0xd5/0x170\n[   32.144031]  exportfs_encode_inode_fh+0x12f/0x300\n[   32.144425]  show_mark_fhandle+0xbe/0x1f0\n[   32.145805]  inotify_fdinfo+0x226/0x2d0\n[   32.146442]  inotify_show_fdinfo+0x1c5/0x350\n[   32.147168]  seq_show+0x530/0x6f0\n[   32.147449]  seq_read_iter+0x503/0x12a0\n[   32.148419]  seq_read+0x31f/0x410\n[   32.150714]  vfs_read+0x1f0/0x9e0\n[   32.152297]  ksys_read+0x125/0x240\n\nIOW ovl_check_encode_origin derefs inode->i_sb->s_root, after it was set\nto NULL in the unmount path.\n\nFix it by protecting calling exportfs_encode_fid() from\nshow_mark_fhandle() with s_umount lock.\n\nThis form of fix was suggested by Amir in [1].\n\n[1]: https://lore.kernel.org/all/CAOQ4uxhbDwhb+2Brs1UdkoF0a3NSdBAOQPNfEHjahrgoKJpLEw@mail.gmail.com/"}],"providerMetadata":{"dateUpdated":"2026-05-23T16:01:45.934Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/950b604384fd75d62e860bec7135b2b62eb4d508"},{"url":"https://git.kernel.org/stable/c/bc1c6b803e14ea2b8f7e33b7164013f666ceb656"},{"url":"https://git.kernel.org/stable/c/3f307a9f7a7a2822e38ac451b73e2244e7279496"},{"url":"https://git.kernel.org/stable/c/d1894bc542becb0fda61e7e513b09523cab44030"},{"url":"https://git.kernel.org/stable/c/a7c4bb43bfdc2b9f06ee9d036028ed13a83df42a"}],"title":"fs/notify: call exportfs_encode_fid with s_umount","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2025-40237","datePublished":"2025-12-04T15:31:27.325Z","dateReserved":"2025-04-16T07:20:57.181Z","dateUpdated":"2026-05-23T16:01:45.934Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2025-12-04 16:16:16","lastModifiedDate":"2026-10-19 21:10:00","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2025","CveId":"40237","Ordinal":"1","Title":"fs/notify: call exportfs_encode_fid with s_umount","CVE":"CVE-2025-40237","Year":"2025"},"notes":[{"CveYear":"2025","CveId":"40237","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nfs/notify: call exportfs_encode_fid with s_umount\n\nCalling intotify_show_fdinfo() on fd watching an overlayfs inode, while\nthe overlayfs is being unmounted, can lead to dereferencing NULL ptr.\n\nThis issue was found by syzkaller.\n\nRace Condition Diagram:\n\nThread 1                           Thread 2\n--------                           --------\n\ngeneric_shutdown_super()\n shrink_dcache_for_umount\n  sb->s_root = NULL\n\n                    |\n                    |             vfs_read()\n                    |              inotify_fdinfo()\n                    |               * inode get from mark *\n                    |               show_mark_fhandle(m, inode)\n                    |                exportfs_encode_fid(inode, ..)\n                    |                 ovl_encode_fh(inode, ..)\n                    |                  ovl_check_encode_origin(inode)\n                    |                   * deref i_sb->s_root *\n                    |\n                    |\n                    v\n fsnotify_sb_delete(sb)\n\nWhich then leads to:\n\n[   32.133461] Oops: general protection fault, probably for non-canonical address 0xdffffc0000000006: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN NOPTI\n[   32.134438] KASAN: null-ptr-deref in range [0x0000000000000030-0x0000000000000037]\n[   32.135032] CPU: 1 UID: 0 PID: 4468 Comm: systemd-coredum Not tainted 6.17.0-rc6 #22 PREEMPT(none)\n\n<snip registers, unreliable trace>\n\n[   32.143353] Call Trace:\n[   32.143732]  ovl_encode_fh+0xd5/0x170\n[   32.144031]  exportfs_encode_inode_fh+0x12f/0x300\n[   32.144425]  show_mark_fhandle+0xbe/0x1f0\n[   32.145805]  inotify_fdinfo+0x226/0x2d0\n[   32.146442]  inotify_show_fdinfo+0x1c5/0x350\n[   32.147168]  seq_show+0x530/0x6f0\n[   32.147449]  seq_read_iter+0x503/0x12a0\n[   32.148419]  seq_read+0x31f/0x410\n[   32.150714]  vfs_read+0x1f0/0x9e0\n[   32.152297]  ksys_read+0x125/0x240\n\nIOW ovl_check_encode_origin derefs inode->i_sb->s_root, after it was set\nto NULL in the unmount path.\n\nFix it by protecting calling exportfs_encode_fid() from\nshow_mark_fhandle() with s_umount lock.\n\nThis form of fix was suggested by Amir in [1].\n\n[1]: https://lore.kernel.org/all/CAOQ4uxhbDwhb+2Brs1UdkoF0a3NSdBAOQPNfEHjahrgoKJpLEw@mail.gmail.com/","Type":"Description","Title":"fs/notify: call exportfs_encode_fid with s_umount"}]}}}