{"id":"CVE-2026-99092","state":"PUBLISHED","title":"riscv: patch: fix handling of bpf-jit execmem addresses","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nriscv: patch: fix handling of bpf-jit execmem addresses\n\nCommit 8718e5a3090b (\"riscv: patch: skip fixmap mapping when kernel text\nis already writable\") gated the core_kernel_text() branch of patch_map()\non CONFIG_STRICT_KERNEL_RWX, and explicitly left the vmalloc branch\nunchanged. That branch has a separate problem.\n\nThat branch only creates a temporary writable fixmap alias when\nCONFIG_STRICT_MODULE_RWX is enabled, and otherwise assumes the target is\ndirectly writable and returns the address unchanged. That assumption no\nlonger holds: bpf_prog_pack_alloc calls set_memory_rox() on every pack\nunconditionally in alloc_new_pack(), independently of any\nCONFIG_STRICT_*_RWX option, so BPF text in the vmalloc area is read-only\nregardless of what CONFIG_STRICT_MODULE_RWX says.\n\nWith CONFIG_STRICT_MODULE_RWX=n, patch_map() returns the read-only\naddress directly, the subsequent copy_to_kernel_nofault() takes a\npage fault and returns -EFAULT. bpf_arch_text_copy() turns that into\n-EINVAL, which propagates through bpf_jit_binary_pack_finalize() to the\nWARN_ON() in bpf_int_jit_compile() and leaves the program un-JITed.\n\nNote that BPF cannot be fixed the way kprobes was in\ncommit bdc46e507b59 (\"riscv: mm: make EXECMEM_KPROBES writable without\nCONFIG_STRICT_MODULE_RWX\"). EXECMEM_BPF is already PAGE_KERNEL, i.e.\nwritable at allocation time; the read-only mapping is established\nafterwards by generic code in alloc_new_pack(), which arch code cannot\ninfluence. The only place this can be handled is patch_map().\n\nThis is the same problem that was fixed on arm64 by commit b1480ed230ac\n(\"arm64: patching: fix handling of execmem addresses\"), and the fix is\nthe same: CONFIG_EXECMEM is what actually tracks whether the vmalloc\narea can hold executable memory that needs a temporary alias to be\nwritten. CONFIG_BPF_JIT, CONFIG_KPROBES and CONFIG_MODULES all select\nit.\n\nNote that this is not limited to CONFIG_MODULES=n. Unlike arm64, riscv\nselects CONFIG_ARCH_OPTIONAL_KERNEL_RWX, so CONFIG_STRICT_MODULE_RWX can\nbe disabled with CONFIG_MODULES=y as well, and the bug is reachable in\nthat configuration too.\n\nThe !CONFIG_MMU build is unaffected: it has its own __patch_insn_set()\nand __patch_insn_write() implementations and never calls patch_map().","publishedAt":"2026-10-26T14:52:00.860Z","updatedAt":"2026-10-26T14:52:00.860Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"2c9e5d4a008293407836d29d35dfd4353615bd2f","status":"affected","lessThan":"562a35b9e0b3d9483d9472995219cadb3592db3d","versionType":"git"},{"version":"2c9e5d4a008293407836d29d35dfd4353615bd2f","status":"affected","lessThan":"9e8fc7972b398e9dc2415ece283d8f64edac3858","versionType":"git"},{"version":"2c9e5d4a008293407836d29d35dfd4353615bd2f","status":"affected","lessThan":"f71d6ea3843c8038c431c2699482f246aea37ca0","versionType":"git"},{"version":"2c9e5d4a008293407836d29d35dfd4353615bd2f","status":"affected","lessThan":"a510e1ae8c9030750c2edf7b0bc9b186cd8c7a06","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["arch/riscv/kernel/patch.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.10","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.10","versionType":"semver"},{"version":"6.12.114","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.58","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.11","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["arch/riscv/kernel/patch.c"]}],"references":["https://git.kernel.org/stable/c/562a35b9e0b3d9483d9472995219cadb3592db3d","https://git.kernel.org/stable/c/9e8fc7972b398e9dc2415ece283d8f64edac3858","https://git.kernel.org/stable/c/f71d6ea3843c8038c431c2699482f246aea37ca0","https://git.kernel.org/stable/c/a510e1ae8c9030750c2edf7b0bc9b186cd8c7a06"],"weaknesses":[],"ingestedAt":"2026-10-29T20:13:43.249Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/99xxx/CVE-2026-99092.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-99092","state":"PUBLISHED","datePublished":"2026-10-26T14:52:00.860Z","dateUpdated":"2026-10-26T14:52:00.860Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-25T10:25:14.390Z"},"containers":{"cna":{"title":"riscv: patch: fix handling of bpf-jit execmem addresses","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nriscv: patch: fix handling of bpf-jit execmem addresses\n\nCommit 8718e5a3090b (\"riscv: patch: skip fixmap mapping when kernel text\nis already writable\") gated the core_kernel_text() branch of patch_map()\non CONFIG_STRICT_KERNEL_RWX, and explicitly left the vmalloc branch\nunchanged. That branch has a separate problem.\n\nThat branch only creates a temporary writable fixmap alias when\nCONFIG_STRICT_MODULE_RWX is enabled, and otherwise assumes the target is\ndirectly writable and returns the address unchanged. That assumption no\nlonger holds: bpf_prog_pack_alloc calls set_memory_rox() on every pack\nunconditionally in alloc_new_pack(), independently of any\nCONFIG_STRICT_*_RWX option, so BPF text in the vmalloc area is read-only\nregardless of what CONFIG_STRICT_MODULE_RWX says.\n\nWith CONFIG_STRICT_MODULE_RWX=n, patch_map() returns the read-only\naddress directly, the subsequent copy_to_kernel_nofault() takes a\npage fault and returns -EFAULT. bpf_arch_text_copy() turns that into\n-EINVAL, which propagates through bpf_jit_binary_pack_finalize() to the\nWARN_ON() in bpf_int_jit_compile() and leaves the program un-JITed.\n\nNote that BPF cannot be fixed the way kprobes was in\ncommit bdc46e507b59 (\"riscv: mm: make EXECMEM_KPROBES writable without\nCONFIG_STRICT_MODULE_RWX\"). EXECMEM_BPF is already PAGE_KERNEL, i.e.\nwritable at allocation time; the read-only mapping is established\nafterwards by generic code in alloc_new_pack(), which arch code cannot\ninfluence. The only place this can be handled is patch_map().\n\nThis is the same problem that was fixed on arm64 by commit b1480ed230ac\n(\"arm64: patching: fix handling of execmem addresses\"), and the fix is\nthe same: CONFIG_EXECMEM is what actually tracks whether the vmalloc\narea can hold executable memory that needs a temporary alias to be\nwritten. CONFIG_BPF_JIT, CONFIG_KPROBES and CONFIG_MODULES all select\nit.\n\nNote that this is not limited to CONFIG_MODULES=n. Unlike arm64, riscv\nselects CONFIG_ARCH_OPTIONAL_KERNEL_RWX, so CONFIG_STRICT_MODULE_RWX can\nbe disabled with CONFIG_MODULES=y as well, and the bug is reachable in\nthat configuration too.\n\nThe !CONFIG_MMU build is unaffected: it has its own __patch_insn_set()\nand __patch_insn_write() implementations and never calls patch_map()."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"2c9e5d4a008293407836d29d35dfd4353615bd2f","status":"affected","lessThan":"562a35b9e0b3d9483d9472995219cadb3592db3d","versionType":"git"},{"version":"2c9e5d4a008293407836d29d35dfd4353615bd2f","status":"affected","lessThan":"9e8fc7972b398e9dc2415ece283d8f64edac3858","versionType":"git"},{"version":"2c9e5d4a008293407836d29d35dfd4353615bd2f","status":"affected","lessThan":"f71d6ea3843c8038c431c2699482f246aea37ca0","versionType":"git"},{"version":"2c9e5d4a008293407836d29d35dfd4353615bd2f","status":"affected","lessThan":"a510e1ae8c9030750c2edf7b0bc9b186cd8c7a06","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["arch/riscv/kernel/patch.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.10","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.10","versionType":"semver"},{"version":"6.12.114","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.58","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.11","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["arch/riscv/kernel/patch.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/562a35b9e0b3d9483d9472995219cadb3592db3d"},{"url":"https://git.kernel.org/stable/c/9e8fc7972b398e9dc2415ece283d8f64edac3858"},{"url":"https://git.kernel.org/stable/c/f71d6ea3843c8038c431c2699482f246aea37ca0"},{"url":"https://git.kernel.org/stable/c/a510e1ae8c9030750c2edf7b0bc9b186cd8c7a06"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-26T14:52:00.860Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.10","versionEndExcluding":"6.12.114"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.10","versionEndExcluding":"6.18.58"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.10","versionEndExcluding":"7.2.11"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.10","versionEndExcluding":"7.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}