{"id":"CVE-2026-90291","state":"PUBLISHED","title":"module/dups: Fix use-after-free in kmod_dup_req lifetime handling","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nmodule/dups: Fix use-after-free in kmod_dup_req lifetime handling\n\nThe kmod dups code uses RCU to ensure that a kmod_dup_req instance is freed\nonly after it is no longer referenced. When releasing an instance, the\nkmod_dup_request_delete() function removes the kmod_dup_req from the\ndup_kmod_reqs list, waits via synchronize_rcu() and finally frees it.\nHowever, this doesn't work correctly because parallel users referencing the\ninstance in kmod_dup_request_exists_wait() don't enter an RCU read-side\ncritical section. This can result in a use-after-free.\n\nThe kmod_dup_request_exists_wait() function may need to hold a valid\nreference to a kmod_dup_req instance across a blocking wait until the\ncorresponding modprobe command completes. This makes it unsuitable for RCU.\n\nFix the issue by changing the lifecycle management of kmod_dup_req to use\nreference counting.","publishedAt":"2026-09-17T16:08:18.700Z","updatedAt":"2026-10-21T12:50:49.946Z","severity":{"score":7.8,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"8660484ed1cf3261e89e0bad94c6395597e87599","status":"affected","lessThan":"a3205bd1f218053575589b14caf8df667f344134","versionType":"git"},{"version":"8660484ed1cf3261e89e0bad94c6395597e87599","status":"affected","lessThan":"2c85e0fb528e039aa8ea1e9c2a1f64347f990541","versionType":"git"},{"version":"8660484ed1cf3261e89e0bad94c6395597e87599","status":"affected","lessThan":"b2709aad7599f6fd957939b60f4a8323c8f08072","versionType":"git"},{"version":"8660484ed1cf3261e89e0bad94c6395597e87599","status":"affected","lessThan":"cd2396fc9684d2cfd3f3c3f09c79d6d9d725b0ca","versionType":"git"},{"version":"8660484ed1cf3261e89e0bad94c6395597e87599","status":"affected","lessThan":"5eecb11b543f9f417bcf0dea239ff99c6af65dbd","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/module/dups.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.4","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.4","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.110","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.52","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.6","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/module/dups.c"]}],"references":["https://git.kernel.org/stable/c/a3205bd1f218053575589b14caf8df667f344134","https://git.kernel.org/stable/c/2c85e0fb528e039aa8ea1e9c2a1f64347f990541","https://git.kernel.org/stable/c/b2709aad7599f6fd957939b60f4a8323c8f08072","https://git.kernel.org/stable/c/cd2396fc9684d2cfd3f3c3f09c79d6d9d725b0ca","https://git.kernel.org/stable/c/5eecb11b543f9f417bcf0dea239ff99c6af65dbd"],"weaknesses":[],"ingestedAt":"2026-10-29T20:13:34.582Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/90xxx/CVE-2026-90291.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-90291","state":"PUBLISHED","datePublished":"2026-09-17T16:08:18.700Z","dateUpdated":"2026-10-21T12:50:49.946Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-11T19:38:34.798Z"},"containers":{"cna":{"title":"module/dups: Fix use-after-free in kmod_dup_req lifetime handling","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nmodule/dups: Fix use-after-free in kmod_dup_req lifetime handling\n\nThe kmod dups code uses RCU to ensure that a kmod_dup_req instance is freed\nonly after it is no longer referenced. When releasing an instance, the\nkmod_dup_request_delete() function removes the kmod_dup_req from the\ndup_kmod_reqs list, waits via synchronize_rcu() and finally frees it.\nHowever, this doesn't work correctly because parallel users referencing the\ninstance in kmod_dup_request_exists_wait() don't enter an RCU read-side\ncritical section. This can result in a use-after-free.\n\nThe kmod_dup_request_exists_wait() function may need to hold a valid\nreference to a kmod_dup_req instance across a blocking wait until the\ncorresponding modprobe command completes. This makes it unsuitable for RCU.\n\nFix the issue by changing the lifecycle management of kmod_dup_req to use\nreference counting."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"8660484ed1cf3261e89e0bad94c6395597e87599","status":"affected","lessThan":"a3205bd1f218053575589b14caf8df667f344134","versionType":"git"},{"version":"8660484ed1cf3261e89e0bad94c6395597e87599","status":"affected","lessThan":"2c85e0fb528e039aa8ea1e9c2a1f64347f990541","versionType":"git"},{"version":"8660484ed1cf3261e89e0bad94c6395597e87599","status":"affected","lessThan":"b2709aad7599f6fd957939b60f4a8323c8f08072","versionType":"git"},{"version":"8660484ed1cf3261e89e0bad94c6395597e87599","status":"affected","lessThan":"cd2396fc9684d2cfd3f3c3f09c79d6d9d725b0ca","versionType":"git"},{"version":"8660484ed1cf3261e89e0bad94c6395597e87599","status":"affected","lessThan":"5eecb11b543f9f417bcf0dea239ff99c6af65dbd","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/module/dups.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.4","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.4","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.110","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.52","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.6","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/module/dups.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/a3205bd1f218053575589b14caf8df667f344134"},{"url":"https://git.kernel.org/stable/c/2c85e0fb528e039aa8ea1e9c2a1f64347f990541"},{"url":"https://git.kernel.org/stable/c/b2709aad7599f6fd957939b60f4a8323c8f08072"},{"url":"https://git.kernel.org/stable/c/cd2396fc9684d2cfd3f3c3f09c79d6d9d725b0ca"},{"url":"https://git.kernel.org/stable/c/5eecb11b543f9f417bcf0dea239ff99c6af65dbd"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - The UAF is in kmod_dup_request_exists_wait(), reached from __request_module() when tracking a duplicate autoload. An unprivileged process hits that via socket(2) → __sys_socket() → __sock_create(), which calls request_module(\"net-pf-%d\") for an unloaded protocol family; the trigger is that local syscall, not a remote protocol message.\nAC:L - The attacker drives both sides: one socket() call's request_module() inserts a kmod_dup_req and kmod_dup_request_announce() queues kmod_dup_request_delete() for 60*HZ, then further socket() calls look up that entry, drop kmod_dup_mutex, and wait_for_completion_state() on first_req_done without rcu_read_lock, racing the delayed kfree.\nPR:L - __request_module() has no capable() check; it only calls security_kernel_module_request(), whose default LSM hook returns 0. __sock_create()'s request_module(\"net-pf-%d\") path has no capability gate either, so a normal unprivileged local user can trigger the duplicate-autoload race.\nUI:N - The attacker issues their own socket() syscalls to force concurrent request_module() calls for the same net-pf-%d name; no other user must mount a filesystem, open a file, or otherwise cooperate.\nS:U - The use-after-free is of a kmalloc'd kmod_dup_req in kernel/module/dups.c and corrupts host kernel heap. That is a standard in-kernel privilege-escalation impact inside one security authority, not a VM or IOMMU boundary crossing.\nC:H - After kmod_dup_request_delete() kfree()s the kmod_dup_req, a racing kmod_dup_request_exists_wait() still reads kmod_req->dup_ret and takes first_req_done.wait.lock inside wait_for_common(). Reclaiming that slab lets the attacker control those contents, a UAF read primitive.\nI:H - wait_for_common() takes first_req_done.wait.lock and can __prepare_to_swait() onto the completion wait queue in the already-freed kmod_dup_req. Heap spraying that object yields an attacker-controlled wait-queue/list write, a UAF write and control-flow hijack primitive.\nA:H - Using a freed kmod_dup_req's completion spinlock in wait_for_common(), or kfree() racing wait_for_completion_state(&kmod_req->first_req_done), oopses or panics the kernel even without a full exploit."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-21T12:50:49.946Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.4","versionEndExcluding":"6.6.160"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.4","versionEndExcluding":"6.12.110"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.4","versionEndExcluding":"6.18.52"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.4","versionEndExcluding":"7.2.6"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.4","versionEndExcluding":"7.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}