CVE-2025-38017

{"id": "CVE-2025-38017", "cveTags": [], "metrics": {"cvssMetricV31": [{"type": "Primary", "source": "[email protected]", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 5.5, "attackVector": "LOCAL", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "LOW", "confidentialityImpact": "NONE"}, "impactScore": 3.6, "exploitabilityScore": 1.8}]}, "published": "2025-06-18T10:15:33.310", "references": [{"url": "https://git.kernel.org/stable/c/7631dca012593c95d36199082546a24a0058fc50", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/d9ec73301099ec5975505e1c3effbe768bab9490", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Primary", "source": "[email protected]", "description": [{"lang": "en", "value": "NVD-CWE-noinfo"}]}], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nfs/eventpoll: fix endless busy loop after timeout has expired\n\nAfter commit 0a65bc27bd64 (\"eventpoll: Set epoll timeout if it's in\nthe future\"), the following program would immediately enter a busy\nloop in the kernel:\n\n```\nint main() {\n int e = epoll_create1(0);\n struct epoll_event event = {.events = EPOLLIN};\n epoll_ctl(e, EPOLL_CTL_ADD, 0, &event);\n const struct timespec timeout = {.tv_nsec = 1};\n epoll_pwait2(e, &event, 1, &timeout, 0);\n}\n```\n\nThis happens because the given (non-zero) timeout of 1 nanosecond\nusually expires before ep_poll() is entered and then\nep_schedule_timeout() returns false, but `timed_out` is never set\nbecause the code line that sets it is skipped. This quickly turns\ninto a soft lockup, RCU stalls and deadlocks, inflicting severe\nheadaches to the whole system.\n\nWhen the timeout has expired, we don't need to schedule a hrtimer, but\nwe should set the `timed_out` variable. Therefore, I suggest moving\nthe ep_schedule_timeout() check into the `timed_out` expression\ninstead of skipping it.\n\nbrauner: Note that there was an earlier fix by Joe Damato in response to\nmy bug report in [1]."}, {"lang": "es", "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: fs/eventpoll: corrige un bucle ocupado sin fin despu\u00e9s de que expira el tiempo de espera Despu\u00e9s de el commit 0a65bc27bd64 (\"eventpoll: establece el tiempo de espera de epoll si es en el futuro\"), el siguiente programa ingresar\u00eda inmediatamente en un bucle ocupado en el kernel: ``` int main() { int e = epoll_create1(0); struct epoll_event event = {.events = EPOLLIN}; epoll_ctl(e, EPOLL_CTL_ADD, 0, &event); const struct timespec timeout = {.tv_nsec = 1}; epoll_pwait2(e, &event, 1, &timeout, 0); } ``` Esto sucede porque el tiempo de espera dado (distinto de cero) de 1 nanosegundo generalmente expira antes de que se ingrese ep_poll() y luego ep_schedule_timeout() devuelve falso, pero `timed_out` nunca se establece porque se omite la l\u00ednea de c\u00f3digo que lo establece. Esto r\u00e1pidamente se convierte en un bloqueo suave, RCU se bloquea y se bloquea, lo que inflige graves dolores de cabeza a todo el sistema. Cuando el tiempo de espera ha expirado, no necesitamos programar un hrtimer, pero debemos establecer la variable `timed_out`. Por lo tanto, sugiero mover la comprobaci\u00f3n de ep_schedule_timeout() a la expresi\u00f3n `timed_out` en lugar de omitirla. brauner: Tenga en cuenta que hubo una correcci\u00f3n anterior por Joe Damato en respuesta a mi informe de error en [1]."}], "lastModified": "2025-11-14T19:01:41.973", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "73E279AE-4280-48EB-9798-AD37FE6F3D9D", "versionEndExcluding": "6.14.8", "versionStartIncluding": "6.14.4"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.15:rc3:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "13FC0DDE-E513-465E-9E81-515702D49B74"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.15:rc4:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "8C7B5B0E-4EEB-48F5-B4CF-0935A7633845"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.15:rc5:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "2D240580-3048-49B2-9E27-F115A9DF8224"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.15:rc6:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "90320558-E553-4EF5-8A0B-0F5D20113BD2"}], "operator": "OR"}]}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}