{"id":"CVE-2025-38067","title":"rseq: Fix segfault on registration when rseq_cs is non-zero","summary":"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 …","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= d7822b1e24f2df5df98c76f0e94a5416349ff759 < 48900d839a3454050fd5822e34be8d54c4ec9b86","Linux >= d7822b1e24f2df5df98c76f0e94a5416349ff759 < 3e4028ef31b69286c9d4878cee0330235f53f218","Linux >= d7822b1e24f2df5df98c76f0e94a5416349ff759 < b2b05d0dc2f4f0646922068af435aed5763d16ba","Linux >= d7822b1e24f2df5df98c76f0e94a5416349ff759 < eaf112069a904b6207b4106ff083e0208232a2eb","Linux >= d7822b1e24f2df5df98c76f0e94a5416349ff759 < f004f58d18a2d3dc761cf973ad27b4a5997bd876","Linux >= d7822b1e24f2df5df98c76f0e94a5416349ff759 < 2df285dab00fa03a3ef939b6cb0d0d0aeb0791db","Linux >= d7822b1e24f2df5df98c76f0e94a5416349ff759 < fd881d0a085fc54354414aed990ccf05f282ba53","Linux 4.18"],"published":"2025-06-18","updated":"2026-10-15","sourceUpdated":"2026-10-15T01:06:26.314Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2025-38067","references":[{"url":"https://git.kernel.org/stable/c/48900d839a3454050fd5822e34be8d54c4ec9b86"},{"url":"https://git.kernel.org/stable/c/3e4028ef31b69286c9d4878cee0330235f53f218"},{"url":"https://git.kernel.org/stable/c/b2b05d0dc2f4f0646922068af435aed5763d16ba"},{"url":"https://git.kernel.org/stable/c/eaf112069a904b6207b4106ff083e0208232a2eb"},{"url":"https://git.kernel.org/stable/c/f004f58d18a2d3dc761cf973ad27b4a5997bd876"},{"url":"https://git.kernel.org/stable/c/2df285dab00fa03a3ef939b6cb0d0d0aeb0791db"},{"url":"https://git.kernel.org/stable/c/fd881d0a085fc54354414aed990ccf05f282ba53"}],"tags":["cve.org"],"epss":0.0058,"epssPercentile":0.47506,"ingestedAt":"2026-10-15T05:52:46.097Z","slug":"CVE-2025-38067","body":"## Overview\n\nIn 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.\n\n## Affected\n\n- `Linux >= d7822b1e24f2df5df98c76f0e94a5416349ff759 < 48900d839a3454050fd5822e34be8d54c4ec9b86`\n- `Linux >= d7822b1e24f2df5df98c76f0e94a5416349ff759 < 3e4028ef31b69286c9d4878cee0330235f53f218`\n- `Linux >= d7822b1e24f2df5df98c76f0e94a5416349ff759 < b2b05d0dc2f4f0646922068af435aed5763d16ba`\n- `Linux >= d7822b1e24f2df5df98c76f0e94a5416349ff759 < eaf112069a904b6207b4106ff083e0208232a2eb`\n- `Linux >= d7822b1e24f2df5df98c76f0e94a5416349ff759 < f004f58d18a2d3dc761cf973ad27b4a5997bd876`\n- `Linux >= d7822b1e24f2df5df98c76f0e94a5416349ff759 < 2df285dab00fa03a3ef939b6cb0d0d0aeb0791db`\n- `Linux >= d7822b1e24f2df5df98c76f0e94a5416349ff759 < fd881d0a085fc54354414aed990ccf05f282ba53`\n- `Linux 4.18`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}