{"id":"CVE-2026-98888","summary":"arm64: kprobes: Allow reentering kprobes while single-stepping","details":"In the Linux kernel, the following vulnerability has been resolved:\n\narm64: kprobes: Allow reentering kprobes while single-stepping\n\nA kprobe can be hit while another kprobe is in KPROBE_HIT_SS state. This\ncan happen when tracing or perf code runs from the debug exception path\nwhile the first kprobe is preparing or executing its out-of-line\nsingle-step instruction.\n\nCurrently arm64 treats a kprobe hit in KPROBE_HIT_SS as unrecoverable,\nthe same as a hit in KPROBE_REENTER. This is too strict. A hit in\nKPROBE_HIT_SS is still a one-level reentry and can be handled by saving\nthe current kprobe state and setting up single-step for the new probe,\njust like reentry from KPROBE_HIT_ACTIVE or KPROBE_HIT_SSDONE.\n\nThe truly unrecoverable case is hitting another kprobe while already in\nKPROBE_REENTER, because the reentry save area has already been consumed.\n\nMove KPROBE_HIT_SS to the recoverable reentry cases and leave\nKPROBE_REENTER as the unrecoverable nested reentry case.\n\nThis change also requires saving saved_irqflag in struct prev_kprobe.\nWhen a nested kprobe calls kprobes_save_local_irqflag(), it overwrites\nkcb-\u003esaved_irqflag with the currently masked DAIF value, losing the\nouter kprobe's original DAIF state. Without this fix, when the outer\nkprobe's single-step finishes, kprobes_restore_local_irqflag() applies\nthe wrong DAIF mask and leaves interrupts permanently disabled.\n\nExtend struct prev_kprobe with a saved_irqflag field and save/restore it\nalongside kp and status. This ensures the outer kprobe's original\ninterrupt state is preserved across reentry.\n\nThis mirrors the x86 fix in commit 6a5022a56ac3\n(\"kprobes/x86: Allow to handle reentered kprobe on single-stepping\").","modified":"2026-10-28T02:33:45.777409589Z","published":"2026-10-23T11:37:46.984Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98888.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/1f342b3e44c3035a837b53b217d816f7511c0d0a"},{"type":"WEB","url":"https://git.kernel.org/stable/c/23f851ac0078a908bf3422d6467ebc1db5828c46"},{"type":"WEB","url":"https://git.kernel.org/stable/c/68774caca799e9695db56d426c69acebd041c2ed"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a21bf9cb893126e8d9730995708d0be5eb167652"},{"type":"WEB","url":"https://git.kernel.org/stable/c/bb0fe9121aa0824211aafa33c7d0151fd25ddb75"},{"type":"WEB","url":"https://git.kernel.org/stable/c/c8e84e292ed4cfc199824146da71bb4397b02a1f"},{"type":"WEB","url":"https://git.kernel.org/stable/c/f96a0606de6bcc8d937b80e6470fd7a174c17e26"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98888.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98888"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"2dd0e8d2d2a157dbc83295a78336c2217110f2f8"},{"fixed":"bb0fe9121aa0824211aafa33c7d0151fd25ddb75"},{"fixed":"f96a0606de6bcc8d937b80e6470fd7a174c17e26"},{"fixed":"1f342b3e44c3035a837b53b217d816f7511c0d0a"},{"fixed":"c8e84e292ed4cfc199824146da71bb4397b02a1f"},{"fixed":"68774caca799e9695db56d426c69acebd041c2ed"},{"fixed":"a21bf9cb893126e8d9730995708d0be5eb167652"},{"fixed":"23f851ac0078a908bf3422d6467ebc1db5828c46"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-98888.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.8.0"},{"fixed":"5.10.271"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.222"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.189"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.158"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.111"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.53"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-98888.json"}}],"schema_version":"1.9.2"}