{"id":"CVE-2026-90140","state":"PUBLISHED","title":"cuse: wait for pending RCU callbacks on module exit","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ncuse: wait for pending RCU callbacks on module exit\n\nSince commit 053fc4f755ad (\"fuse: fix UAF in rcu pathwalks\"),\nfuse_conn_put() frees the fuse_conn through call_rcu() rather than\nsynchronously. For cuse, fc->release is cuse_fc_release(), which\nlives in the cuse module. If the module is removed before the RCU\ngrace period ends, the callback jumps into freed module memory:\n\n userspace / module unload | RCU softirq\n~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\n close(/dev/cuse) |\n cuse_channel_release() |\n fuse_dev_release() |\n fuse_conn_put(fch->conn) |\n call_rcu(delayed_release) ------+---> callback queued\n |\n rmmod cuse |\n cuse_exit() |\n cuse_channel_destroy() |\n ... |\n return |\n |\n |\n | rcu_do_batch()\n | delayed_release()\n | fc->release()\n | -> cuse_fc_release()\n | ^^^ freed text!\n\nThe freed module text is unmapped by vfree(), so the jump into the\nstale callback triggers a page-fault Oops. If the virtual address\nis subsequently reused, the callback could execute unrelated code\n(undefined behaviour).\n\nFix this by calling rcu_barrier() in cuse_exit() so that any pending\nfuse_conn release callback completes before the module is removed.","publishedAt":"2026-09-17T16:06:37.824Z","updatedAt":"2026-10-19T08:58:38.281Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"bfbab62ca69f72bcd14ea30de1fb98f6080ad464","status":"affected","lessThan":"7fe415e1cd8fa875be263670c0ab47109818abb6","versionType":"git"},{"version":"a8f650b93e55764ca9ff8e1ddebc151f57024086","status":"affected","lessThan":"45ae914b2f6ea56fc2f1c017fdee4e995bcb4c0e","versionType":"git"},{"version":"535e9bd0e8f8d8cfdc29de7cdb902b5041427fe6","status":"affected","lessThan":"ac5c499413385cea3e0220d6050408d50842891d","versionType":"git"},{"version":"053fc4f755ad43cf35210677bcba798ccdc48d0c","status":"affected","lessThan":"a1b46aee33d83f14ed62d7fdef1a91d3e0b732a9","versionType":"git"},{"version":"053fc4f755ad43cf35210677bcba798ccdc48d0c","status":"affected","lessThan":"389bd349ddbcf90dbd8a4f2a4ab6e552d53df134","versionType":"git"},{"version":"053fc4f755ad43cf35210677bcba798ccdc48d0c","status":"affected","lessThan":"c40f3f24839f8404325a2099e26c2a04786ae309","versionType":"git"},{"version":"053fc4f755ad43cf35210677bcba798ccdc48d0c","status":"affected","lessThan":"4deb3edead0c0e172cc7349e8855d741d3c5e162","versionType":"git"},{"version":"5.15.166","status":"affected","lessThan":"5.15.221","versionType":"semver"},{"version":"6.1.107","status":"affected","lessThan":"6.1.188","versionType":"semver"},{"version":"6.6.48","status":"affected","lessThan":"6.6.157","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/fuse/cuse.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.8","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.8","versionType":"semver"},{"version":"5.15.221","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.188","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.157","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":["fs/fuse/cuse.c"]}],"references":["https://git.kernel.org/stable/c/7fe415e1cd8fa875be263670c0ab47109818abb6","https://git.kernel.org/stable/c/45ae914b2f6ea56fc2f1c017fdee4e995bcb4c0e","https://git.kernel.org/stable/c/ac5c499413385cea3e0220d6050408d50842891d","https://git.kernel.org/stable/c/a1b46aee33d83f14ed62d7fdef1a91d3e0b732a9","https://git.kernel.org/stable/c/389bd349ddbcf90dbd8a4f2a4ab6e552d53df134","https://git.kernel.org/stable/c/c40f3f24839f8404325a2099e26c2a04786ae309","https://git.kernel.org/stable/c/4deb3edead0c0e172cc7349e8855d741d3c5e162"],"weaknesses":[],"ingestedAt":"2026-10-29T20:13:34.582Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/90xxx/CVE-2026-90140.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-90140","state":"PUBLISHED","datePublished":"2026-09-17T16:06:37.824Z","dateUpdated":"2026-10-19T08:58:38.281Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-11T19:38:34.789Z"},"containers":{"cna":{"title":"cuse: wait for pending RCU callbacks on module exit","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\ncuse: wait for pending RCU callbacks on module exit\n\nSince commit 053fc4f755ad (\"fuse: fix UAF in rcu pathwalks\"),\nfuse_conn_put() frees the fuse_conn through call_rcu() rather than\nsynchronously. For cuse, fc->release is cuse_fc_release(), which\nlives in the cuse module. If the module is removed before the RCU\ngrace period ends, the callback jumps into freed module memory:\n\n userspace / module unload | RCU softirq\n~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\n close(/dev/cuse) |\n cuse_channel_release() |\n fuse_dev_release() |\n fuse_conn_put(fch->conn) |\n call_rcu(delayed_release) ------+---> callback queued\n |\n rmmod cuse |\n cuse_exit() |\n cuse_channel_destroy() |\n ... |\n return |\n |\n |\n | rcu_do_batch()\n | delayed_release()\n | fc->release()\n | -> cuse_fc_release()\n | ^^^ freed text!\n\nThe freed module text is unmapped by vfree(), so the jump into the\nstale callback triggers a page-fault Oops. If the virtual address\nis subsequently reused, the callback could execute unrelated code\n(undefined behaviour).\n\nFix this by calling rcu_barrier() in cuse_exit() so that any pending\nfuse_conn release callback completes before the module is removed."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"bfbab62ca69f72bcd14ea30de1fb98f6080ad464","status":"affected","lessThan":"7fe415e1cd8fa875be263670c0ab47109818abb6","versionType":"git"},{"version":"a8f650b93e55764ca9ff8e1ddebc151f57024086","status":"affected","lessThan":"45ae914b2f6ea56fc2f1c017fdee4e995bcb4c0e","versionType":"git"},{"version":"535e9bd0e8f8d8cfdc29de7cdb902b5041427fe6","status":"affected","lessThan":"ac5c499413385cea3e0220d6050408d50842891d","versionType":"git"},{"version":"053fc4f755ad43cf35210677bcba798ccdc48d0c","status":"affected","lessThan":"a1b46aee33d83f14ed62d7fdef1a91d3e0b732a9","versionType":"git"},{"version":"053fc4f755ad43cf35210677bcba798ccdc48d0c","status":"affected","lessThan":"389bd349ddbcf90dbd8a4f2a4ab6e552d53df134","versionType":"git"},{"version":"053fc4f755ad43cf35210677bcba798ccdc48d0c","status":"affected","lessThan":"c40f3f24839f8404325a2099e26c2a04786ae309","versionType":"git"},{"version":"053fc4f755ad43cf35210677bcba798ccdc48d0c","status":"affected","lessThan":"4deb3edead0c0e172cc7349e8855d741d3c5e162","versionType":"git"},{"version":"5.15.166","status":"affected","lessThan":"5.15.221","versionType":"semver"},{"version":"6.1.107","status":"affected","lessThan":"6.1.188","versionType":"semver"},{"version":"6.6.48","status":"affected","lessThan":"6.6.157","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/fuse/cuse.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.8","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.8","versionType":"semver"},{"version":"5.15.221","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.188","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.157","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":["fs/fuse/cuse.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/7fe415e1cd8fa875be263670c0ab47109818abb6"},{"url":"https://git.kernel.org/stable/c/45ae914b2f6ea56fc2f1c017fdee4e995bcb4c0e"},{"url":"https://git.kernel.org/stable/c/ac5c499413385cea3e0220d6050408d50842891d"},{"url":"https://git.kernel.org/stable/c/a1b46aee33d83f14ed62d7fdef1a91d3e0b732a9"},{"url":"https://git.kernel.org/stable/c/389bd349ddbcf90dbd8a4f2a4ab6e552d53df134"},{"url":"https://git.kernel.org/stable/c/c40f3f24839f8404325a2099e26c2a04786ae309"},{"url":"https://git.kernel.org/stable/c/4deb3edead0c0e172cc7349e8855d741d3c5e162"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-19T08:58:38.281Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15.166","versionEndExcluding":"5.15.221"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.1.107","versionEndExcluding":"6.1.188"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.6.48","versionEndExcluding":"6.6.157"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.8","versionEndExcluding":"6.12.110"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.8","versionEndExcluding":"6.18.52"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.8","versionEndExcluding":"7.2.6"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.8","versionEndExcluding":"7.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}