{"id":"AZL-63977","summary":"CVE-2025-38067 affecting package kernel for versions less than 6.6.104.2-1","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nrseq: Fix segfault on registration when rseq_cs is non-zero\n\nThe rseq_cs field is documented as being set to 0 by user-space prior to\nregistration, however this is not currently enforced by the kernel. This\ncan result in a segfault on return to user-space if the value stored in\nthe rseq_cs field doesn't point to a valid struct rseq_cs.\n\nThe correct solution to this would be to fail the rseq registration when\nthe rseq_cs field is non-zero. However, some older versions of glibc\nwill reuse the rseq area of previous threads without clearing the\nrseq_cs field and will also terminate the process if the rseq\nregistration fails in a secondary thread. This wasn't caught in testing\nbecause in this case the leftover rseq_cs does point to a valid struct\nrseq_cs.\n\nWhat we can do is clear the rseq_cs field on registration when it's\nnon-zero which will prevent segfaults on registration and won't break\nthe glibc versions that reuse rseq areas on thread creation.","modified":"2026-04-01T05:20:48.420512Z","published":"2025-06-18T10:15:39Z","upstream":["CVE-2025-38067"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-38067"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:3","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.6.104.2-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-63977.json"}}],"schema_version":"1.7.5"}