{"id":"CVE-2026-23380","summary":"tracing: Fix WARN_ON in tracing_buffers_mmap_close","details":"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.","modified":"2026-04-02T13:12:23.373216Z","published":"2026-03-25T10:27:59.682Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/23xxx/CVE-2026-23380.json","cna_assigner":"Linux"},"references":[{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"},{"type":"WEB","url":"https://git.kernel.org/stable/c/91f3e8d84c89918769e71393f839c9fefadc2580"},{"type":"WEB","url":"https://git.kernel.org/stable/c/b0f269ba6fefe9e3cb9feedcf78fcd0b633800c0"},{"type":"WEB","url":"https://git.kernel.org/stable/c/cdd96641b64297a2db42676f051362b76280a58b"},{"type":"WEB","url":"https://git.kernel.org/stable/c/e39bb9e02b68942f8e9359d2a3efe7d37ae6be0e"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/23xxx/CVE-2026-23380.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-23380"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"cf9f0f7c4c5bb45e7bb270e48bab6f7837825a64"},{"fixed":"91f3e8d84c89918769e71393f839c9fefadc2580"},{"fixed":"cdd96641b64297a2db42676f051362b76280a58b"},{"fixed":"b0f269ba6fefe9e3cb9feedcf78fcd0b633800c0"},{"fixed":"e39bb9e02b68942f8e9359d2a3efe7d37ae6be0e"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-23380.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.10.0"},{"fixed":"6.12.77"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.17"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"6.19.7"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-23380.json"}}],"schema_version":"1.7.5"}