{"id":"CVE-2025-39904","state":"PUBLISHED","title":"arm64: kexec: initialize kexec_buf struct in load_other_segments()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\narm64: kexec: initialize kexec_buf struct in load_other_segments()\n\nPatch series \"kexec: Fix invalid field access\".\n\nThe kexec_buf structure was previously declared without initialization. \ncommit bf454ec31add (\"kexec_file: allow to place kexec_buf randomly\")\nadded a field that is always read but not consistently populated by all\narchitectures.  This un-initialized field will contain garbage.\n\nThis is also triggering a UBSAN warning when the uninitialized data was\naccessed:\n\n\t------------[ cut here ]------------\n\tUBSAN: invalid-load in ./include/linux/kexec.h:210:10\n\tload of value 252 is not a valid value for type '_Bool'\n\nZero-initializing kexec_buf at declaration ensures all fields are cleanly\nset, preventing future instances of uninitialized memory being used.\n\nAn initial fix was already landed for arm64[0], and this patchset fixes\nthe problem on the remaining arm64 code and on riscv, as raised by Mark.\n\nDiscussions about this problem could be found at[1][2].\n\n\nThis patch (of 3):\n\nThe kexec_buf structure was previously declared without initialization.\ncommit bf454ec31add (\"kexec_file: allow to place kexec_buf randomly\")\nadded a field that is always read but not consistently populated by all\narchitectures. This un-initialized field will contain garbage.\n\nThis is also triggering a UBSAN warning when the uninitialized data was\naccessed:\n\n\t------------[ cut here ]------------\n\tUBSAN: invalid-load in ./include/linux/kexec.h:210:10\n\tload of value 252 is not a valid value for type '_Bool'\n\nZero-initializing kexec_buf at declaration ensures all fields are\ncleanly set, preventing future instances of uninitialized memory being\nused.","publishedAt":"2025-10-01T07:44:27.739Z","updatedAt":"2026-05-11T21:38:39.363Z","severity":{"score":5.5,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","source":"CISA-ADP"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"bf454ec31add6790f6cdc88328e38901fcbbade6","status":"affected","lessThan":"340cc9a3bd30b25edaf6a9708d41b5f2c10a054a","versionType":"git"},{"version":"bf454ec31add6790f6cdc88328e38901fcbbade6","status":"affected","lessThan":"04d3cd43700a2d0fe4bfb1012a8ec7f2e34a3507","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["arch/arm64/kernel/machine_kexec_file.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.16","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.16","versionType":"semver"},{"version":"6.16.8","status":"unaffected","lessThanOrEqual":"6.16.*","versionType":"semver"},{"version":"6.17","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["arch/arm64/kernel/machine_kexec_file.c"]}],"references":["https://git.kernel.org/stable/c/340cc9a3bd30b25edaf6a9708d41b5f2c10a054a","https://git.kernel.org/stable/c/04d3cd43700a2d0fe4bfb1012a8ec7f2e34a3507"],"weaknesses":["CWE-908"],"ingestedAt":"2026-10-29T20:09:09.358Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2025/39xxx/CVE-2025-39904.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2025-39904","state":"PUBLISHED","datePublished":"2025-10-01T07:44:27.739Z","dateUpdated":"2026-05-11T21:38:39.363Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2025-04-16T07:20:57.146Z"},"containers":{"cna":{"title":"arm64: kexec: initialize kexec_buf struct in load_other_segments()","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\narm64: kexec: initialize kexec_buf struct in load_other_segments()\n\nPatch series \"kexec: Fix invalid field access\".\n\nThe kexec_buf structure was previously declared without initialization. \ncommit bf454ec31add (\"kexec_file: allow to place kexec_buf randomly\")\nadded a field that is always read but not consistently populated by all\narchitectures.  This un-initialized field will contain garbage.\n\nThis is also triggering a UBSAN warning when the uninitialized data was\naccessed:\n\n\t------------[ cut here ]------------\n\tUBSAN: invalid-load in ./include/linux/kexec.h:210:10\n\tload of value 252 is not a valid value for type '_Bool'\n\nZero-initializing kexec_buf at declaration ensures all fields are cleanly\nset, preventing future instances of uninitialized memory being used.\n\nAn initial fix was already landed for arm64[0], and this patchset fixes\nthe problem on the remaining arm64 code and on riscv, as raised by Mark.\n\nDiscussions about this problem could be found at[1][2].\n\n\nThis patch (of 3):\n\nThe kexec_buf structure was previously declared without initialization.\ncommit bf454ec31add (\"kexec_file: allow to place kexec_buf randomly\")\nadded a field that is always read but not consistently populated by all\narchitectures. This un-initialized field will contain garbage.\n\nThis is also triggering a UBSAN warning when the uninitialized data was\naccessed:\n\n\t------------[ cut here ]------------\n\tUBSAN: invalid-load in ./include/linux/kexec.h:210:10\n\tload of value 252 is not a valid value for type '_Bool'\n\nZero-initializing kexec_buf at declaration ensures all fields are\ncleanly set, preventing future instances of uninitialized memory being\nused."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"bf454ec31add6790f6cdc88328e38901fcbbade6","status":"affected","lessThan":"340cc9a3bd30b25edaf6a9708d41b5f2c10a054a","versionType":"git"},{"version":"bf454ec31add6790f6cdc88328e38901fcbbade6","status":"affected","lessThan":"04d3cd43700a2d0fe4bfb1012a8ec7f2e34a3507","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["arch/arm64/kernel/machine_kexec_file.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.16","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.16","versionType":"semver"},{"version":"6.16.8","status":"unaffected","lessThanOrEqual":"6.16.*","versionType":"semver"},{"version":"6.17","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["arch/arm64/kernel/machine_kexec_file.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/340cc9a3bd30b25edaf6a9708d41b5f2c10a054a"},{"url":"https://git.kernel.org/stable/c/04d3cd43700a2d0fe4bfb1012a8ec7f2e34a3507"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-05-11T21:38:39.363Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.16","versionEndExcluding":"6.16.8"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.16","versionEndExcluding":"6.17"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"cvssV3_1":{"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"}},{"other":{"type":"ssvc","content":{"id":"CVE-2025-39904","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"version":"2.0.3","timestamp":"2026-01-14T19:30:11.300750Z"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-908","lang":"en","type":"CWE","description":"CWE-908 Use of Uninitialized Resource"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-01-14T19:33:14.694Z"}}]}}}