{"id":"CVE-2026-23417","summary":"bpf: Fix constant blinding for PROBE_MEM32 stores","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix constant blinding for PROBE_MEM32 stores\n\nBPF_ST | BPF_PROBE_MEM32 immediate stores are not handled by\nbpf_jit_blind_insn(), allowing user-controlled 32-bit immediates to\nsurvive unblinded into JIT-compiled native code when bpf_jit_harden \u003e= 1.\n\nThe root cause is that convert_ctx_accesses() rewrites BPF_ST|BPF_MEM\nto BPF_ST|BPF_PROBE_MEM32 for arena pointer stores during verification,\nbefore bpf_jit_blind_constants() runs during JIT compilation. The\nblinding switch only matches BPF_ST|BPF_MEM (mode 0x60), not\nBPF_ST|BPF_PROBE_MEM32 (mode 0xa0). The instruction falls through\nunblinded.\n\nAdd BPF_ST|BPF_PROBE_MEM32 cases to bpf_jit_blind_insn() alongside the\nexisting BPF_ST|BPF_MEM cases. The blinding transformation is identical:\nload the blinded immediate into BPF_REG_AX via mov+xor, then convert\nthe immediate store to a register store (BPF_STX).\n\nThe rewritten STX instruction must preserve the BPF_PROBE_MEM32 mode so\nthe architecture JIT emits the correct arena addressing (R12-based on\nx86-64). Cannot use the BPF_STX_MEM() macro here because it hardcodes\nBPF_MEM mode; construct the instruction directly instead.","modified":"2026-06-02T18:29:32.299608986Z","published":"2026-04-02T11:40:57.837Z","related":["SUSE-SU-2026:21841-1","SUSE-SU-2026:21845-1","SUSE-SU-2026:21860-1","openSUSE-SU-2026:20826-1"],"database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/23xxx/CVE-2026-23417.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/2321a9596d2260310267622e0ad8fbfa6f95378f"},{"type":"WEB","url":"https://git.kernel.org/stable/c/56af722756ed82fee2ae5d5b4d04743407506195"},{"type":"WEB","url":"https://git.kernel.org/stable/c/ccbf29b28b5554f9d65b2fb53b994673ad58b3bf"},{"type":"WEB","url":"https://git.kernel.org/stable/c/de641ea08f8fff6906e169d2576c2ac54e562fbb"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/23xxx/CVE-2026-23417.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-23417"},{"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":"6082b6c328b5486da2b356eae94b8b83c98b5565"},{"fixed":"56af722756ed82fee2ae5d5b4d04743407506195"},{"fixed":"ccbf29b28b5554f9d65b2fb53b994673ad58b3bf"},{"fixed":"de641ea08f8fff6906e169d2576c2ac54e562fbb"},{"fixed":"2321a9596d2260310267622e0ad8fbfa6f95378f"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-23417.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.9.0"},{"fixed":"6.12.80"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.21"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"6.19.11"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-23417.json"}}],"schema_version":"1.7.5"}