{"id":"CVE-2026-23380","state":"PUBLISHED","title":"tracing: Fix WARN_ON in tracing_buffers_mmap_close","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ntracing: Fix WARN_ON in tracing_buffers_mmap_close\n\nWhen a process forks, the child process copies the parent's VMAs but the\nuser_mapped reference count is not incremented. As a result, when both the\nparent and child processes exit, tracing_buffers_mmap_close() is called\ntwice. On the second call, user_mapped is already 0, causing the function to\nreturn -ENODEV and triggering a WARN_ON.\n\nNormally, this isn't an issue as the memory is mapped with VM_DONTCOPY set.\nBut this is only a hint, and the application can call\nmadvise(MADVISE_DOFORK) which resets the VM_DONTCOPY flag. When the\napplication does that, it can trigger this issue on fork.\n\nFix it by incrementing the user_mapped reference count without re-mapping\nthe pages in the VMA's open callback.","publishedAt":"2026-03-25T10:27:59.682Z","updatedAt":"2026-05-11T22:05:45.422Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"cf9f0f7c4c5bb45e7bb270e48bab6f7837825a64","status":"affected","lessThan":"91f3e8d84c89918769e71393f839c9fefadc2580","versionType":"git"},{"version":"cf9f0f7c4c5bb45e7bb270e48bab6f7837825a64","status":"affected","lessThan":"cdd96641b64297a2db42676f051362b76280a58b","versionType":"git"},{"version":"cf9f0f7c4c5bb45e7bb270e48bab6f7837825a64","status":"affected","lessThan":"b0f269ba6fefe9e3cb9feedcf78fcd0b633800c0","versionType":"git"},{"version":"cf9f0f7c4c5bb45e7bb270e48bab6f7837825a64","status":"affected","lessThan":"e39bb9e02b68942f8e9359d2a3efe7d37ae6be0e","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["include/linux/ring_buffer.h","kernel/trace/ring_buffer.c","kernel/trace/trace.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.10","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.10","versionType":"semver"},{"version":"6.12.77","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.17","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19.7","status":"unaffected","lessThanOrEqual":"6.19.*","versionType":"semver"},{"version":"7.0","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["include/linux/ring_buffer.h","kernel/trace/ring_buffer.c","kernel/trace/trace.c"]}],"references":["https://git.kernel.org/stable/c/91f3e8d84c89918769e71393f839c9fefadc2580","https://git.kernel.org/stable/c/cdd96641b64297a2db42676f051362b76280a58b","https://git.kernel.org/stable/c/b0f269ba6fefe9e3cb9feedcf78fcd0b633800c0","https://git.kernel.org/stable/c/e39bb9e02b68942f8e9359d2a3efe7d37ae6be0e"],"weaknesses":[],"ingestedAt":"2026-10-29T20:11:21.040Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/23xxx/CVE-2026-23380.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-23380","state":"PUBLISHED","datePublished":"2026-03-25T10:27:59.682Z","dateUpdated":"2026-05-11T22:05:45.422Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-01-13T15:37:46.007Z"},"containers":{"cna":{"title":"tracing: Fix WARN_ON in tracing_buffers_mmap_close","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\ntracing: Fix WARN_ON in tracing_buffers_mmap_close\n\nWhen a process forks, the child process copies the parent's VMAs but the\nuser_mapped reference count is not incremented. As a result, when both the\nparent and child processes exit, tracing_buffers_mmap_close() is called\ntwice. On the second call, user_mapped is already 0, causing the function to\nreturn -ENODEV and triggering a WARN_ON.\n\nNormally, this isn't an issue as the memory is mapped with VM_DONTCOPY set.\nBut this is only a hint, and the application can call\nmadvise(MADVISE_DOFORK) which resets the VM_DONTCOPY flag. When the\napplication does that, it can trigger this issue on fork.\n\nFix it by incrementing the user_mapped reference count without re-mapping\nthe pages in the VMA's open callback."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"cf9f0f7c4c5bb45e7bb270e48bab6f7837825a64","status":"affected","lessThan":"91f3e8d84c89918769e71393f839c9fefadc2580","versionType":"git"},{"version":"cf9f0f7c4c5bb45e7bb270e48bab6f7837825a64","status":"affected","lessThan":"cdd96641b64297a2db42676f051362b76280a58b","versionType":"git"},{"version":"cf9f0f7c4c5bb45e7bb270e48bab6f7837825a64","status":"affected","lessThan":"b0f269ba6fefe9e3cb9feedcf78fcd0b633800c0","versionType":"git"},{"version":"cf9f0f7c4c5bb45e7bb270e48bab6f7837825a64","status":"affected","lessThan":"e39bb9e02b68942f8e9359d2a3efe7d37ae6be0e","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["include/linux/ring_buffer.h","kernel/trace/ring_buffer.c","kernel/trace/trace.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.10","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.10","versionType":"semver"},{"version":"6.12.77","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.17","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19.7","status":"unaffected","lessThanOrEqual":"6.19.*","versionType":"semver"},{"version":"7.0","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["include/linux/ring_buffer.h","kernel/trace/ring_buffer.c","kernel/trace/trace.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/91f3e8d84c89918769e71393f839c9fefadc2580"},{"url":"https://git.kernel.org/stable/c/cdd96641b64297a2db42676f051362b76280a58b"},{"url":"https://git.kernel.org/stable/c/b0f269ba6fefe9e3cb9feedcf78fcd0b633800c0"},{"url":"https://git.kernel.org/stable/c/e39bb9e02b68942f8e9359d2a3efe7d37ae6be0e"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-05-11T22:05:45.422Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.10","versionEndExcluding":"6.12.77"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.10","versionEndExcluding":"6.18.17"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.10","versionEndExcluding":"6.19.7"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.10","versionEndExcluding":"7.0"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}