{"id":"CVE-2026-98552","state":"PUBLISHED","title":"perf/core: Fix a refcount leak in attach_perf_ctx_data()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nperf/core: Fix a refcount leak in attach_perf_ctx_data()\n\nThe attach_perf_ctx_data() can race on global and !global cases.  The\nglobal case is protected by global_ctx_data_rwsem and shares a single\nreference count using perf_ctx_data.global field.\n\nBut when it races with !global case, it may miss to set the global field\nand result in a reference count leak.\n\n CPU1                                  CPU2\n ----------------------------------------------------------------\n attach_task_ctx_data(.global=1)       attach_task_ctx_data(.global=0)\n   cd1 = alloc_perf_ctx_data();          cd2 = alloc_perf_ctx_data();\n                                         //    { .global = 0, .refcount = 1 };\n\n                                         try_cmpxchg(); // success,\n                                         // task->perf_ctx_data = cd2\n   try_cmpxhg(); // fail; old = cd2\n   refcount_inc_not_zero(&old->refcount); // success\n     // old.refcount = 2\n   free_perf_ctx_data(cd1);\n\nThen later detach_global_ctx_data() will see the data but it's not\nmarked as global, so it won't call detach_task_ctx_data().","publishedAt":"2026-10-18T15:18:19.810Z","updatedAt":"2026-10-19T09:21:35.261Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"506e64e710ff9573fd2b86686528762b7901b5e4","status":"affected","lessThan":"23250517cd475367653f1e99396967f54c6f1b7c","versionType":"git"},{"version":"506e64e710ff9573fd2b86686528762b7901b5e4","status":"affected","lessThan":"5286d4eb5cd7e10d7d93c3cc596e18bc8ad80f72","versionType":"git"},{"version":"506e64e710ff9573fd2b86686528762b7901b5e4","status":"affected","lessThan":"cca4980630b3c7a85f53cb43c6018184ce5d4e37","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/events/core.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.15","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.15","versionType":"semver"},{"version":"6.18.55","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.9","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/events/core.c"]}],"references":["https://git.kernel.org/stable/c/23250517cd475367653f1e99396967f54c6f1b7c","https://git.kernel.org/stable/c/5286d4eb5cd7e10d7d93c3cc596e18bc8ad80f72","https://git.kernel.org/stable/c/cca4980630b3c7a85f53cb43c6018184ce5d4e37"],"weaknesses":[],"ingestedAt":"2026-10-29T20:13:43.249Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/98xxx/CVE-2026-98552.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-98552","state":"PUBLISHED","datePublished":"2026-10-18T15:18:19.810Z","dateUpdated":"2026-10-19T09:21:35.261Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-25T10:25:14.356Z"},"containers":{"cna":{"title":"perf/core: Fix a refcount leak in attach_perf_ctx_data()","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nperf/core: Fix a refcount leak in attach_perf_ctx_data()\n\nThe attach_perf_ctx_data() can race on global and !global cases.  The\nglobal case is protected by global_ctx_data_rwsem and shares a single\nreference count using perf_ctx_data.global field.\n\nBut when it races with !global case, it may miss to set the global field\nand result in a reference count leak.\n\n CPU1                                  CPU2\n ----------------------------------------------------------------\n attach_task_ctx_data(.global=1)       attach_task_ctx_data(.global=0)\n   cd1 = alloc_perf_ctx_data();          cd2 = alloc_perf_ctx_data();\n                                         //    { .global = 0, .refcount = 1 };\n\n                                         try_cmpxchg(); // success,\n                                         // task->perf_ctx_data = cd2\n   try_cmpxhg(); // fail; old = cd2\n   refcount_inc_not_zero(&old->refcount); // success\n     // old.refcount = 2\n   free_perf_ctx_data(cd1);\n\nThen later detach_global_ctx_data() will see the data but it's not\nmarked as global, so it won't call detach_task_ctx_data()."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"506e64e710ff9573fd2b86686528762b7901b5e4","status":"affected","lessThan":"23250517cd475367653f1e99396967f54c6f1b7c","versionType":"git"},{"version":"506e64e710ff9573fd2b86686528762b7901b5e4","status":"affected","lessThan":"5286d4eb5cd7e10d7d93c3cc596e18bc8ad80f72","versionType":"git"},{"version":"506e64e710ff9573fd2b86686528762b7901b5e4","status":"affected","lessThan":"cca4980630b3c7a85f53cb43c6018184ce5d4e37","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/events/core.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.15","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.15","versionType":"semver"},{"version":"6.18.55","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.9","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/events/core.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/23250517cd475367653f1e99396967f54c6f1b7c"},{"url":"https://git.kernel.org/stable/c/5286d4eb5cd7e10d7d93c3cc596e18bc8ad80f72"},{"url":"https://git.kernel.org/stable/c/cca4980630b3c7a85f53cb43c6018184ce5d4e37"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-19T09:21:35.261Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.15","versionEndExcluding":"6.18.55"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.15","versionEndExcluding":"7.2.9"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.15","versionEndExcluding":"7.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}