{"id":"CVE-2026-98044","summary":"bpf: Reject legacy packet loads from callbacks","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Reject legacy packet loads from callbacks\n\ncheck_ld_abs() models a failed BPF_LD_ABS or BPF_LD_IND in a\nsubprogram as an implicit return with R0 set to zero. It calls\nprepare_func_exit() to explore this synthesized path.\n\nWhen the load is reached directly from a synchronous callback,\nprepare_func_exit() enforces the callback return contract and marks R0\nprecise. R0 is not derived from a real instruction on this path, so\nprecision backtracking reaches the callback call with R0 still requested\nand triggers the \"callback unexpected regs\" verifier bug. A privileged\nprogram loader can therefore cause a verifier warning and an -EFAULT\nBPF_PROG_LOAD.\n\nThese legacy packet-load instructions are deprecated. Reject them from\ncallbacks rather than complicating their implicit-return model. Check all\nactive frames before constructing the implicit return so nested static\nsubprograms cannot hide the callback context.\n\nGlobal functions are verified independently with a fresh frame zero, so\nan active-frame check cannot identify a global function called from a\ncallback. Also check the complete subprogram call graph during stack-depth\nvalidation and reject a function containing a legacy load when any caller\nis a callback. This covers global and static descendants without making\nhas_ld_abs transitive, preserving its per-function BTF return-type check.\nOrdinary uses outside callbacks remain supported.","modified":"2026-11-13T04:07:25.582244139Z","published":"2026-09-25T10:23:55.454Z","related":["SUSE-SU-2026:24550-1","SUSE-SU-2026:24619-1","SUSE-SU-2026:24643-1","SUSE-SU-2026:24648-1","SUSE-SU-2026:24651-1","SUSE-SU-2026:24662-1","SUSE-SU-2026:5091-1","openSUSE-SU-2026:12074-1"],"database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98044.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/3484a99303912db62428494a9061212049027e57"},{"type":"WEB","url":"https://git.kernel.org/stable/c/bc489c0c9b8c86bd7fac42cfd1bb152f042fca56"},{"type":"WEB","url":"https://git.kernel.org/stable/c/cebda2a2bb4183550eae9dcf888c16407b4fffda"},{"type":"WEB","url":"https://git.kernel.org/stable/c/e7d28823c662128caae63f14e16bd394916c139b"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98044.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98044"},{"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":"8674e2db06cff6b50f2216eed9a761d15425bb34"},{"fixed":"cebda2a2bb4183550eae9dcf888c16407b4fffda"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"ce01a4e5cfac7adbe0be565f90cd32ecbb2f8337"},{"fixed":"3484a99303912db62428494a9061212049027e57"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"ee861486e377edc55361c08dcbceab3f6b6577bd"},{"fixed":"bc489c0c9b8c86bd7fac42cfd1bb152f042fca56"},{"fixed":"e7d28823c662128caae63f14e16bd394916c139b"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"928d354ae3557e8f755a227e67be88034eb3cd7f"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"8a800497d9f6c2ec9c2c1ba7b71d0ac2ea7f7bbe"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"de1055e7f9e67af32b1f3376066272b04e5223c0"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"37ad2bb11e9de92cb7b94548705eeedd87f7d392"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"d846d83bdacbd8f14fc45c63b8c1d22608452e1c"}]}],"versions":["v6.12.113","v6.12.112","v6.12.111","v6.12.110","v6.12.109","v6.12.108","v6.12.107","v6.12.106","v6.12.105","v6.12.104","v6.12.103","v6.12.102","v6.12.101","v6.18.52","v6.18.51","v6.18.50","v6.18.49","v6.18.48","v6.18.47","v6.18.46","v6.18.45","v6.18.44","v6.18.43","v6.18.42","v5.10.274","v5.10.273","v5.10.272","v5.10.271","v5.10.270","v5.10.269","v5.10.268","v5.10.267","v5.10.266","v5.10.265","v5.15.225","v5.15.224","v5.15.223","v5.15.222","v5.15.221","v5.15.220","v5.15.219","v5.15.218","v5.15.217","v5.15.216","v6.1.192","v6.1.191","v6.1.190","v6.1.189","v6.1.188","v6.1.187","v6.1.186","v6.1.185","v6.1.184","v6.1.183","v6.6.162","v6.6.161","v6.6.160","v6.6.159","v6.6.158","v6.6.157","v6.6.156","v6.6.155","v6.6.154","v6.6.153","v6.6.152","v6.6.151","v6.6.150","v6.6.149","v6.6.148","v7.0.14","v7.0.13","v7.0.12","v7.0.11","v7.0.10"],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-98044.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"5.10.265"},{"fixed":"5.11"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.15.216"},{"fixed":"5.16"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.1.183"},{"fixed":"6.2"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.6.148"},{"fixed":"6.7"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.12.101"},{"fixed":"6.12.114"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.18.42"},{"fixed":"6.18.53"}]},{"type":"ECOSYSTEM","events":[{"introduced":"7.0.10"},{"fixed":"7.1"}]},{"type":"ECOSYSTEM","events":[{"introduced":"7.1.0"},{"fixed":"7.2.7"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-98044.json"}}],"schema_version":"1.9.2"}