{"id":"CVE-2026-80778","state":"PUBLISHED","title":"futex/pi: Reject cross-mm private futex owners","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nfutex/pi: Reject cross-mm private futex owners\n\nA private futex key borrows the waiter's mm without taking an mm_users\nreference. Nevertheless, attach_to_pi_owner() currently accepts an owner\nfrom a different address space and copies the private key into the owner's\nPI state.\n\nWhen that owner exits, exit_pi_state_list() uses the saved key to find the\nhash bucket and acquires a reference to the waiter's private hash. If the\nlast user of the waiter's mm exits concurrently, futex_hash_free() frees\nthe hash while the owner still uses its bucket and reference.\n\nPrevent this by validating in attach_to_pi_owner() that, for private\nfutexes, the owner mm and waiter mm are the same. Perform the check with\nthe owner's pi_lock held and after validating owner::futex::state to\nserialize against a concurrent PI-state exit cleanup.\n\n[ tglx: Amended comment ]","publishedAt":"2026-09-04T15:12:50.117Z","updatedAt":"2026-10-19T08:43:33.681Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"80367ad01d93ac781b0e1df246edaf006928002f","status":"affected","lessThan":"2b92e5562653b5293529f63b0300837d9dcedbd7","versionType":"git"},{"version":"80367ad01d93ac781b0e1df246edaf006928002f","status":"affected","lessThan":"f7fb3e07752688842cbe0b85cf0d98c2fbf76b68","versionType":"git"},{"version":"80367ad01d93ac781b0e1df246edaf006928002f","status":"affected","lessThan":"43b148d796aa338858792d0167cebdc12b8cb4b9","versionType":"git"},{"version":"80367ad01d93ac781b0e1df246edaf006928002f","status":"affected","lessThan":"59b3732f95dda1fbd2234514d35f4fb6b5bb6d85","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/futex/pi.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.16","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.16","versionType":"semver"},{"version":"6.18.47","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.11","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2.1","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/futex/pi.c"]}],"references":["https://git.kernel.org/stable/c/2b92e5562653b5293529f63b0300837d9dcedbd7","https://git.kernel.org/stable/c/f7fb3e07752688842cbe0b85cf0d98c2fbf76b68","https://git.kernel.org/stable/c/43b148d796aa338858792d0167cebdc12b8cb4b9","https://git.kernel.org/stable/c/59b3732f95dda1fbd2234514d35f4fb6b5bb6d85"],"weaknesses":[],"ingestedAt":"2026-10-29T20:13:07.220Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/80xxx/CVE-2026-80778.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-80778","state":"PUBLISHED","datePublished":"2026-09-04T15:12:50.117Z","dateUpdated":"2026-10-19T08:43:33.681Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-08-26T14:34:25.792Z"},"containers":{"cna":{"title":"futex/pi: Reject cross-mm private futex owners","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nfutex/pi: Reject cross-mm private futex owners\n\nA private futex key borrows the waiter's mm without taking an mm_users\nreference. Nevertheless, attach_to_pi_owner() currently accepts an owner\nfrom a different address space and copies the private key into the owner's\nPI state.\n\nWhen that owner exits, exit_pi_state_list() uses the saved key to find the\nhash bucket and acquires a reference to the waiter's private hash. If the\nlast user of the waiter's mm exits concurrently, futex_hash_free() frees\nthe hash while the owner still uses its bucket and reference.\n\nPrevent this by validating in attach_to_pi_owner() that, for private\nfutexes, the owner mm and waiter mm are the same. Perform the check with\nthe owner's pi_lock held and after validating owner::futex::state to\nserialize against a concurrent PI-state exit cleanup.\n\n[ tglx: Amended comment ]"}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"80367ad01d93ac781b0e1df246edaf006928002f","status":"affected","lessThan":"2b92e5562653b5293529f63b0300837d9dcedbd7","versionType":"git"},{"version":"80367ad01d93ac781b0e1df246edaf006928002f","status":"affected","lessThan":"f7fb3e07752688842cbe0b85cf0d98c2fbf76b68","versionType":"git"},{"version":"80367ad01d93ac781b0e1df246edaf006928002f","status":"affected","lessThan":"43b148d796aa338858792d0167cebdc12b8cb4b9","versionType":"git"},{"version":"80367ad01d93ac781b0e1df246edaf006928002f","status":"affected","lessThan":"59b3732f95dda1fbd2234514d35f4fb6b5bb6d85","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/futex/pi.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.16","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.16","versionType":"semver"},{"version":"6.18.47","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.11","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2.1","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/futex/pi.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/2b92e5562653b5293529f63b0300837d9dcedbd7"},{"url":"https://git.kernel.org/stable/c/f7fb3e07752688842cbe0b85cf0d98c2fbf76b68"},{"url":"https://git.kernel.org/stable/c/43b148d796aa338858792d0167cebdc12b8cb4b9"},{"url":"https://git.kernel.org/stable/c/59b3732f95dda1fbd2234514d35f4fb6b5bb6d85"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-19T08:43:33.681Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.16","versionEndExcluding":"6.18.47"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.16","versionEndExcluding":"7.1.11"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.16","versionEndExcluding":"7.2.1"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.16","versionEndExcluding":"7.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}