{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-98134", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-25T10:25:14.319Z", "datePublished": "2026-09-25T10:36:12.919Z", "dateUpdated": "2026-10-21T12:54:40.601Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-21T12:54:40.601Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: check_cond_jmp_op(): properly infer if register is null\n\nNicholas Carlini reported a bug when verifier can incorrectly infer\nthat a pointer is non-null. The bug occurs when two pointers are\ncompared and one of them has a type w/o PTR_MAYBE_NULL flag,\nbut which allows a value to be NULL at runtime.\nHere is an example:\n\n // `a` is PTR_TO_MEM | MEM_RDONLY | PTR_UNTRUSTED\n // `a` is 0 at runtime.\n // `b` is PTR_TO_MAP_VALUE | PTR_MAYBE_NULL\n void *a = bpf_rdonly_cast(0, 0);\n int *b = bpf_map_lookup_elem(...);\n\n if (a == b)\n *b = 42; // verifier does not catch null pointer dereference\n\nThis happens because of a special case in check_cond_jmp_op(),\nwhich attempts to strip PTR_MAYBE_NULL flags from pointer types,\nwhen processing comparisons like `rA == rB`, if either rA or rB can't\nbe null.\n\nThe non-null property is derived based on the absence of\nPTR_MAYBE_NULL flag on rA's or rB's type. But that is not sufficient\nfor types like PTR_TO_MEM, as in the example.\n\nThis patch replaces type_may_be_null() call with reg_not_null(),\nwhich contains an allowlist of types for which absence of\nPTR_MAYBE_NULL actually means that the value can't be NULL at runtime.\n\nAt the moment, the list in the reg_not_null() omits two types for\nwhich PTR_MAYBE_NULL is applicable: PTR_TO_XDP_SOCK and PTR_TO_BUF.\nIn order to remain backward compatible, and assuming that only\ncomparison between pointers of the same type makes sense,\nthis commit extends reg_not_null(). W/o such an extension e.g.\nverifier_jeq_infer_not_null/null_ptr_to_map_value fails.\n\nreg_not_null() can be extended further, but I deem that out of scope\nfor the fix at hand. Explicit base_type(...) != PTR_TO_BTF_ID\nchecks in the check_cond_jmp_op() can be removed with migration to\nreg_not_null(), but that is a behavioural change, as the special case\nwould start matching for PTR_TO_BTF_ID that is also is_trusted_reg().\nI omit the behavioural change from this commit." } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "kernel/bpf/verifier.c" ], "versions": [ { "version": "befae75856ab406a3f3fab2aa2118cf3b2dfe3e6", "lessThan": "d51cd486930f5bcfd4b55d55ab8e47b03f93d2ed", "status": "affected", "versionType": "git" }, { "version": "befae75856ab406a3f3fab2aa2118cf3b2dfe3e6", "lessThan": "dfd8f8adda565e08c370c45cf9d6b2511ba9b5c6", "status": "affected", "versionType": "git" }, { "version": "befae75856ab406a3f3fab2aa2118cf3b2dfe3e6", "lessThan": "9bf96b4347f541604b3caadeabda0773d9ceaf2a", "status": "affected", "versionType": "git" }, { "version": "befae75856ab406a3f3fab2aa2118cf3b2dfe3e6", "lessThan": "b55c9f019e169ed0d01394f96e172286a8b21b99", "status": "affected", "versionType": "git" }, { "version": "befae75856ab406a3f3fab2aa2118cf3b2dfe3e6", "lessThan": "d3ef6c097ba078e1f8c7239d76a0ce8b61e75095", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "kernel/bpf/verifier.c" ], "versions": [ { "version": "6.2", "status": "affected" }, { "version": "0", "lessThan": "6.2", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.160", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.114", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.57", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2.7", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.3", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.2", "versionEndExcluding": "6.6.160" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.2", "versionEndExcluding": "6.12.114" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.2", "versionEndExcluding": "6.18.57" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.2", "versionEndExcluding": "7.2.7" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.2", "versionEndExcluding": "7.3" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/d51cd486930f5bcfd4b55d55ab8e47b03f93d2ed" }, { "url": "https://git.kernel.org/stable/c/dfd8f8adda565e08c370c45cf9d6b2511ba9b5c6" }, { "url": "https://git.kernel.org/stable/c/9bf96b4347f541604b3caadeabda0773d9ceaf2a" }, { "url": "https://git.kernel.org/stable/c/b55c9f019e169ed0d01394f96e172286a8b21b99" }, { "url": "https://git.kernel.org/stable/c/d3ef6c097ba078e1f8c7239d76a0ce8b61e75095" } ], "title": "bpf: check_cond_jmp_op(): properly infer if register is null", "x_generator": { "engine": "bippy-1.2.0" } } } }