CVE-2025-71074

{"id": "CVE-2025-71074", "cveTags": [], "metrics": {"cvssMetricV31": [{"type": "Primary", "source": "nvd@nist.gov", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 4.7, "attackVector": "LOCAL", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "HIGH", "availabilityImpact": "HIGH", "privilegesRequired": "LOW", "confidentialityImpact": "NONE"}, "impactScore": 3.6, "exploitabilityScore": 1.0}]}, "affected": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "affectedData": [{"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "ddf8abd2599491cbad959c700b90ba72a5dce8d0", "lessThan": "e5bf5ee266633cb18fff6f98f0b7d59a62819eee", "versionType": "git"}], "programFiles": ["drivers/usb/gadget/function/f_fs.c"], "defaultStatus": "unaffected"}, {"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "2.6.35"}, {"status": "unaffected", "version": "0", "lessThan": "2.6.35", "versionType": "semver"}, {"status": "unaffected", "version": "6.19", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*"}], "programFiles": ["drivers/usb/gadget/function/f_fs.c"], "defaultStatus": "affected"}]}], "published": "2026-01-13T16:16:06.860", "references": [{"url": "https://git.kernel.org/stable/c/e5bf5ee266633cb18fff6f98f0b7d59a62819eee", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Primary", "source": "nvd@nist.gov", "description": [{"lang": "en", "value": "CWE-362"}]}], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nfunctionfs: fix the open/removal races\n\nffs_epfile_open() can race with removal, ending up with file->private_data\npointing to freed object.\n\nThere is a total count of opened files on functionfs (both ep0 and\ndynamic ones) and when it hits zero, dynamic files get removed.\nUnfortunately, that removal can happen while another thread is\nin ffs_epfile_open(), but has not incremented the count yet.\nIn that case open will succeed, leaving us with UAF on any subsequent\nread() or write().\n\nThe root cause is that ffs->opened is misused; atomic_dec_and_test() vs.\natomic_add_return() is not a good idea, when object remains visible all\nalong.\n\nTo untangle that\n\t* serialize openers on ffs->mutex (both for ep0 and for dynamic files)\n\t* have dynamic ones use atomic_inc_not_zero() and fail if we had\nzero ->opened; in that case the file we are opening is doomed.\n\t* have the inodes of dynamic files marked on removal (from the\ncallback of simple_recursive_removal()) - clear ->i_private there.\n\t* have open of dynamic ones verify they hadn't been already removed,\nalong with checking that state is FFS_ACTIVE."}, {"lang": "es", "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad:\n\nfunctionfs: corregir las condiciones de carrera de apertura/eliminaci\u00f3n\n\nffs_epfile_open() puede entrar en condici\u00f3n de carrera con la eliminaci\u00f3n, lo que resulta en que file->private_data apunte a un objeto liberado.\n\nExiste un recuento total de archivos abiertos en functionfs (tanto ep0 como los din\u00e1micos) y cuando llega a cero, los archivos din\u00e1micos se eliminan. Desafortunadamente, esa eliminaci\u00f3n puede ocurrir mientras otro hilo est\u00e1 en ffs_epfile_open(), pero a\u00fan no ha incrementado el recuento. En ese caso, la apertura tendr\u00e1 \u00e9xito, dej\u00e1ndonos con UAF en cualquier read() o write() posterior.\n\nLa causa ra\u00edz es que ffs->opened se utiliza incorrectamente; atomic_dec_and_test() frente a atomic_add_return() no es una buena idea cuando el objeto permanece visible todo el tiempo.\n\nPara desenredar eso\n* serializar los abridores en ffs->mutex (tanto para ep0 como para archivos din\u00e1micos)\n* hacer que los din\u00e1micos usen atomic_inc_not_zero() y fallen si ten\u00edamos cero ->opened; en ese caso, el archivo que estamos abriendo est\u00e1 condenado.\n* hacer que los inodos de los archivos din\u00e1micos se marquen al eliminarse (desde la devoluci\u00f3n de llamada de simple_recursive_removal()) - borrar ->i_private all\u00ed.\n* hacer que la apertura de los din\u00e1micos verifique que no hayan sido ya eliminados, junto con la comprobaci\u00f3n de que el estado es FFS_ACTIVE."}], "lastModified": "2026-06-17T10:03:36.420", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "7F5B9532-DC73-487B-B269-082C453A67EC", "versionEndExcluding": "6.19", "versionStartIncluding": "2.6.35.1"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:2.6.35:-:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "11B11B98-42CE-41C8-A40E-FAA230FD2A76"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.19:rc1:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "17B67AA7-40D6-4AFA-8459-F200F3D7CFD1"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.19:rc2:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "C47E4CC9-C826-4FA9-B014-7FE3D9B318B2"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.19:rc3:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "F71D92C0-C023-48BD-B3B6-70B638EEE298"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.19:rc4:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "13580667-0A98-40CC-B29F-D12790B91BDB"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.19:rc5:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "CAD1FED7-CF48-47BF-AC7D-7B6FA3C065FC"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.19:rc6:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "3EF854A1-ABB1-4E93-BE9A-44569EC76C0D"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.19:rc7:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "F5DC0CA6-F0AF-4DDF-A882-3DADB9A886A7"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.19:rc8:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "EB5B7DFC-C36B-45D8-922C-877569FDDF43"}], "operator": "OR"}]}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}