{"id":"CVE-2025-68250","state":"PUBLISHED","title":"hung_task: fix warnings caused by unaligned lock pointers","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nhung_task: fix warnings caused by unaligned lock pointers\n\nThe blocker tracking mechanism assumes that lock pointers are at least\n4-byte aligned to use their lower bits for type encoding.\n\nHowever, as reported by Eero Tamminen, some architectures like m68k\nonly guarantee 2-byte alignment of 32-bit values. This breaks the\nassumption and causes two related WARN_ON_ONCE checks to trigger.\n\nTo fix this, the runtime checks are adjusted to silently ignore any lock\nthat is not 4-byte aligned, effectively disabling the feature in such\ncases and avoiding the related warnings.\n\nThanks to Geert Uytterhoeven for bisecting!","publishedAt":"2025-12-16T14:32:17.173Z","updatedAt":"2026-08-05T12:10:27.999Z","severity":{"score":8.2,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"e711faaafbe54a884f33b53472434063d342f6d4","status":"affected","lessThan":"c0e2dcbe54cb15ecdf9d8f4501c6720423243888","versionType":"git"},{"version":"e711faaafbe54a884f33b53472434063d342f6d4","status":"affected","lessThan":"c97513cddcfc235f2522617980838e500af21d01","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["include/linux/hung_task.h"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.16","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.16","versionType":"semver"},{"version":"6.17.6","status":"unaffected","lessThanOrEqual":"6.17.*","versionType":"semver"},{"version":"6.18","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["include/linux/hung_task.h"]}],"references":["https://git.kernel.org/stable/c/c0e2dcbe54cb15ecdf9d8f4501c6720423243888","https://git.kernel.org/stable/c/c97513cddcfc235f2522617980838e500af21d01"],"weaknesses":[],"ingestedAt":"2026-10-29T20:09:56.034Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2025/68xxx/CVE-2025-68250.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2025-68250","state":"PUBLISHED","datePublished":"2025-12-16T14:32:17.173Z","dateUpdated":"2026-08-05T12:10:27.999Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2025-12-16T13:41:40.266Z"},"containers":{"cna":{"title":"hung_task: fix warnings caused by unaligned lock pointers","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nhung_task: fix warnings caused by unaligned lock pointers\n\nThe blocker tracking mechanism assumes that lock pointers are at least\n4-byte aligned to use their lower bits for type encoding.\n\nHowever, as reported by Eero Tamminen, some architectures like m68k\nonly guarantee 2-byte alignment of 32-bit values. This breaks the\nassumption and causes two related WARN_ON_ONCE checks to trigger.\n\nTo fix this, the runtime checks are adjusted to silently ignore any lock\nthat is not 4-byte aligned, effectively disabling the feature in such\ncases and avoiding the related warnings.\n\nThanks to Geert Uytterhoeven for bisecting!"}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"e711faaafbe54a884f33b53472434063d342f6d4","status":"affected","lessThan":"c0e2dcbe54cb15ecdf9d8f4501c6720423243888","versionType":"git"},{"version":"e711faaafbe54a884f33b53472434063d342f6d4","status":"affected","lessThan":"c97513cddcfc235f2522617980838e500af21d01","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["include/linux/hung_task.h"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.16","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.16","versionType":"semver"},{"version":"6.17.6","status":"unaffected","lessThanOrEqual":"6.17.*","versionType":"semver"},{"version":"6.18","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["include/linux/hung_task.h"]}],"references":[{"url":"https://git.kernel.org/stable/c/c0e2dcbe54cb15ecdf9d8f4501c6720423243888"},{"url":"https://git.kernel.org/stable/c/c97513cddcfc235f2522617980838e500af21d01"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H","baseScore":8.2,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:N - On an affected m68k system running ksmbd, remote SMB2 IPC-pipe requests can contend on the unaligned session RPC rwsem and reach the vulnerable blocker tracking code over TCP/445.\nAC:L - The client can deterministically trigger the contemporaneous recursive-lock path or control concurrent requests against one session, so exploitation requires no uncontrollable race or memory-layout manipulation.\nPR:N - KSMBD permits passwordless guest sessions and allows restricted guest RPC operations, making the path reachable without credentials in a reasonable guest-enabled deployment.\nUI:N - Once the service is configured, attacker-supplied SMB requests trigger the vulnerable path without victim action.\nS:U - The warning, information exposure, and possible panic affect the same kernel and host security authority as the vulnerable code.\nC:L - The warning dumps kernel addresses and up to 48 raw m68k stack words, providing a bounded information disclosure where the kernel log or console is accessible.\nI:N - The rejected unaligned pointer is never stored or dereferenced, and the bug causes no memory corruption or attacker-controlled data modification.\nA:H - The warning immediately panics the kernel when panic_on_warn is enabled or the warning limit is reached, causing complete host unavailability."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-05T12:10:27.999Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.16","versionEndExcluding":"6.17.6"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.16","versionEndExcluding":"6.18"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}