{"id":"AZL-104492","summary":"CVE-2026-98063 affecting package kernel 6.6.157.1-1","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix NULL-ptr-deref in btf_var_show()\n\nbtf_var_show() calls btf_type_id_resolve() unconditionally, which\ndereferences btf-\u003eresolved_ids. That is NULL for a base BTF - e.g. the\nvmlinux BTF that bpf_snprintf_btf() renders against - since base BTF is\nnot resolved during parsing. btf_modifier_show() guards this with\n'if (btf-\u003eresolved_ids)', but btf_var_show() does not.\n\nA BPF program that passes the type_id of a BTF_KIND_VAR from the vmlinux\nBTF to bpf_snprintf_btf() thus NULL-derefs:\n\nKASAN: probably user-memory-access in range [0x46638-0x4663f]\nRIP: 0010:btf_var_show (kernel/bpf/btf.c:2929)\nCall Trace:\n \u003cTASK\u003e\n btf_type_show (kernel/bpf/btf.c:8259)\n btf_type_snprintf_show (kernel/bpf/btf.c:8329)\n bpf_snprintf_btf (kernel/trace/bpf_trace.c:1047)\n bpf_prog_test_run_raw_tp (net/bpf/test_run.c:829)\n __sys_bpf (kernel/bpf/syscall.c:4804)\n do_syscall_64 (arch/x86/entry/syscall_64.c:84)\n entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121)\n \u003c/TASK\u003e\n\nResolve the var's type directly with btf_type_skip_modifiers() when\nresolved_ids is NULL, mirroring btf_modifier_show().","modified":"2026-09-27T05:34:32Z","published":"2026-09-25T11:17:35Z","upstream":["CVE-2026-98063"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98063"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:3","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"6.6.157.1-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-104492.json"}}],"schema_version":"1.9.0"}