{"id":"CVE-2022-49889","state":"PUBLISHED","title":"ring-buffer: Check for NULL cpu_buffer in ring_buffer_wake_waiters()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nring-buffer: Check for NULL cpu_buffer in ring_buffer_wake_waiters()\n\nOn some machines the number of listed CPUs may be bigger than the actual\nCPUs that exist. The tracing subsystem allocates a per_cpu directory with\naccess to the per CPU ring buffer via a cpuX file. But to save space, the\nring buffer will only allocate buffers for online CPUs, even though the\nCPU array will be as big as the nr_cpu_ids.\n\nWith the addition of waking waiters on the ring buffer when closing the\nfile, the ring_buffer_wake_waiters() now needs to make sure that the\nbuffer is allocated (with the irq_work allocated with it) before trying to\nwake waiters, as it will cause a NULL pointer dereference.\n\nWhile debugging this, I added a NULL check for the buffer itself (which is\nOK to do), and also NULL pointer checks against buffer->buffers (which is\nnot fine, and will WARN) as well as making sure the CPU number passed in\nis within the nr_cpu_ids (which is also not fine if it isn't).\n\n\nBugzilla: https://bugzilla.opensuse.org/show_bug.cgi?id=1204705","publishedAt":"2025-05-01T14:10:33.832Z","updatedAt":"2026-05-23T15:23:09.111Z","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":"2475de2bc0de17fb1b24c5e90194f84b5ca70d3e","status":"affected","lessThan":"b5074df412bf3df9d6ce096b6fa03eb1082d05c9","versionType":"git"},{"version":"f4f15344110d0b5b8822ac97bc8200e71939c945","status":"affected","lessThan":"49ca992f6e50d0f46ec9608f44e011cf3121f389","versionType":"git"},{"version":"f3ddb74ad0790030c9592229fb14d8c451f4e9a8","status":"affected","lessThan":"7433632c9ff68a991bd0bc38cabf354e9d2de410","versionType":"git"},{"version":"5544f411a4e8bc39e6a444badbac37dd0e0caf0a","status":"affected","versionType":"git"},{"version":"5.19.17","status":"affected","lessThan":"5.20","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/trace/ring_buffer.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"5.15.75","status":"affected","lessThan":"5.15.78","versionType":"semver"},{"version":"6.0.3","status":"affected","lessThan":"6.0.8","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/trace/ring_buffer.c"]}],"references":["https://git.kernel.org/stable/c/b5074df412bf3df9d6ce096b6fa03eb1082d05c9","https://git.kernel.org/stable/c/49ca992f6e50d0f46ec9608f44e011cf3121f389","https://git.kernel.org/stable/c/7433632c9ff68a991bd0bc38cabf354e9d2de410"],"weaknesses":["CWE-476"],"ingestedAt":"2026-10-29T20:05:26.763Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2022/49xxx/CVE-2022-49889.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2022-49889","state":"PUBLISHED","datePublished":"2025-05-01T14:10:33.832Z","dateUpdated":"2026-05-23T15:23:09.111Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2025-05-01T14:05:17.242Z"},"containers":{"cna":{"title":"ring-buffer: Check for NULL cpu_buffer in ring_buffer_wake_waiters()","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nring-buffer: Check for NULL cpu_buffer in ring_buffer_wake_waiters()\n\nOn some machines the number of listed CPUs may be bigger than the actual\nCPUs that exist. The tracing subsystem allocates a per_cpu directory with\naccess to the per CPU ring buffer via a cpuX file. But to save space, the\nring buffer will only allocate buffers for online CPUs, even though the\nCPU array will be as big as the nr_cpu_ids.\n\nWith the addition of waking waiters on the ring buffer when closing the\nfile, the ring_buffer_wake_waiters() now needs to make sure that the\nbuffer is allocated (with the irq_work allocated with it) before trying to\nwake waiters, as it will cause a NULL pointer dereference.\n\nWhile debugging this, I added a NULL check for the buffer itself (which is\nOK to do), and also NULL pointer checks against buffer->buffers (which is\nnot fine, and will WARN) as well as making sure the CPU number passed in\nis within the nr_cpu_ids (which is also not fine if it isn't).\n\n\nBugzilla: https://bugzilla.opensuse.org/show_bug.cgi?id=1204705"}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"2475de2bc0de17fb1b24c5e90194f84b5ca70d3e","status":"affected","lessThan":"b5074df412bf3df9d6ce096b6fa03eb1082d05c9","versionType":"git"},{"version":"f4f15344110d0b5b8822ac97bc8200e71939c945","status":"affected","lessThan":"49ca992f6e50d0f46ec9608f44e011cf3121f389","versionType":"git"},{"version":"f3ddb74ad0790030c9592229fb14d8c451f4e9a8","status":"affected","lessThan":"7433632c9ff68a991bd0bc38cabf354e9d2de410","versionType":"git"},{"version":"5544f411a4e8bc39e6a444badbac37dd0e0caf0a","status":"affected","versionType":"git"},{"version":"5.19.17","status":"affected","lessThan":"5.20","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/trace/ring_buffer.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"5.15.75","status":"affected","lessThan":"5.15.78","versionType":"semver"},{"version":"6.0.3","status":"affected","lessThan":"6.0.8","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/trace/ring_buffer.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/b5074df412bf3df9d6ce096b6fa03eb1082d05c9"},{"url":"https://git.kernel.org/stable/c/49ca992f6e50d0f46ec9608f44e011cf3121f389"},{"url":"https://git.kernel.org/stable/c/7433632c9ff68a991bd0bc38cabf354e9d2de410"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-05-23T15:23:09.111Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15.75","versionEndExcluding":"5.15.78"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.0.3","versionEndExcluding":"6.0.8"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.19.17"}]}]}],"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":{"timestamp":"2025-10-01T16:09:57.289350Z","id":"CVE-2022-49889","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-476","type":"CWE","lang":"en","description":"CWE-476 NULL Pointer Dereference"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2025-10-01T16:10:00.993Z"}}]}}}