{"api_version":"1","generated_at":"2026-10-24T07:02:29+00:00","cve":"CVE-2026-98044","urls":{"html":"https://cve.report/CVE-2026-98044","api":"https://cve.report/api/cve/CVE-2026-98044.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-98044","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-98044"},"summary":{"title":"bpf: Reject legacy packet loads from callbacks","description":"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.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-09-25 11:17:33","updated_at":"2026-10-21 13:21:20"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/3484a99303912db62428494a9061212049027e57","name":"https://git.kernel.org/stable/c/3484a99303912db62428494a9061212049027e57","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/e7d28823c662128caae63f14e16bd394916c139b","name":"https://git.kernel.org/stable/c/e7d28823c662128caae63f14e16bd394916c139b","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/bc489c0c9b8c86bd7fac42cfd1bb152f042fca56","name":"https://git.kernel.org/stable/c/bc489c0c9b8c86bd7fac42cfd1bb152f042fca56","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/cebda2a2bb4183550eae9dcf888c16407b4fffda","name":"https://git.kernel.org/stable/c/cebda2a2bb4183550eae9dcf888c16407b4fffda","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-98044","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98044","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 8674e2db06cff6b50f2216eed9a761d15425bb34 cebda2a2bb4183550eae9dcf888c16407b4fffda git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected ce01a4e5cfac7adbe0be565f90cd32ecbb2f8337 3484a99303912db62428494a9061212049027e57 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected ee861486e377edc55361c08dcbceab3f6b6577bd bc489c0c9b8c86bd7fac42cfd1bb152f042fca56 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected ee861486e377edc55361c08dcbceab3f6b6577bd e7d28823c662128caae63f14e16bd394916c139b git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 928d354ae3557e8f755a227e67be88034eb3cd7f git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 8a800497d9f6c2ec9c2c1ba7b71d0ac2ea7f7bbe git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected de1055e7f9e67af32b1f3376066272b04e5223c0 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 37ad2bb11e9de92cb7b94548705eeedd87f7d392 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected d846d83bdacbd8f14fc45c63b8c1d22608452e1c git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.12.101 6.12.114 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.18.42 6.18.53 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5.10.265 5.11 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5.15.216 5.16 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.1.183 6.2 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.6.148 6.7 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 7.0.10 7.1 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 7.1","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.114 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.53 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2.7 7.2.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.3 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"98044","cve":"CVE-2026-98044","epss":"0.001660000","percentile":"0.055130000","score_date":"2026-10-21","updated_at":"2026-10-22 00:15:10"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["kernel/bpf/verifier.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"cebda2a2bb4183550eae9dcf888c16407b4fffda","status":"affected","version":"8674e2db06cff6b50f2216eed9a761d15425bb34","versionType":"git"},{"lessThan":"3484a99303912db62428494a9061212049027e57","status":"affected","version":"ce01a4e5cfac7adbe0be565f90cd32ecbb2f8337","versionType":"git"},{"lessThan":"bc489c0c9b8c86bd7fac42cfd1bb152f042fca56","status":"affected","version":"ee861486e377edc55361c08dcbceab3f6b6577bd","versionType":"git"},{"lessThan":"e7d28823c662128caae63f14e16bd394916c139b","status":"affected","version":"ee861486e377edc55361c08dcbceab3f6b6577bd","versionType":"git"},{"status":"affected","version":"928d354ae3557e8f755a227e67be88034eb3cd7f","versionType":"git"},{"status":"affected","version":"8a800497d9f6c2ec9c2c1ba7b71d0ac2ea7f7bbe","versionType":"git"},{"status":"affected","version":"de1055e7f9e67af32b1f3376066272b04e5223c0","versionType":"git"},{"status":"affected","version":"37ad2bb11e9de92cb7b94548705eeedd87f7d392","versionType":"git"},{"status":"affected","version":"d846d83bdacbd8f14fc45c63b8c1d22608452e1c","versionType":"git"},{"lessThan":"6.12.114","status":"affected","version":"6.12.101","versionType":"semver"},{"lessThan":"6.18.53","status":"affected","version":"6.18.42","versionType":"semver"},{"lessThan":"5.11","status":"affected","version":"5.10.265","versionType":"semver"},{"lessThan":"5.16","status":"affected","version":"5.15.216","versionType":"semver"},{"lessThan":"6.2","status":"affected","version":"6.1.183","versionType":"semver"},{"lessThan":"6.7","status":"affected","version":"6.6.148","versionType":"semver"},{"lessThan":"7.1","status":"affected","version":"7.0.10","versionType":"semver"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["kernel/bpf/verifier.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"7.1"},{"lessThan":"7.1","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.114","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.53","versionType":"semver"},{"lessThanOrEqual":"7.2.*","status":"unaffected","version":"7.2.7","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.3","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.114","versionStartIncluding":"6.12.101","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.53","versionStartIncluding":"6.18.42","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2.7","versionStartIncluding":"7.1","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.3","versionStartIncluding":"7.1","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.10.265","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15.216","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.1.183","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.6.148","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"7.0.10","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"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."}],"providerMetadata":{"dateUpdated":"2026-10-21T12:54:12.833Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/cebda2a2bb4183550eae9dcf888c16407b4fffda"},{"url":"https://git.kernel.org/stable/c/3484a99303912db62428494a9061212049027e57"},{"url":"https://git.kernel.org/stable/c/bc489c0c9b8c86bd7fac42cfd1bb152f042fca56"},{"url":"https://git.kernel.org/stable/c/e7d28823c662128caae63f14e16bd394916c139b"}],"title":"bpf: Reject legacy packet loads from callbacks","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-98044","datePublished":"2026-09-25T10:23:55.454Z","dateReserved":"2026-09-25T10:19:56.071Z","dateUpdated":"2026-10-21T12:54:12.833Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-09-25 11:17:33","lastModifiedDate":"2026-10-21 13:21:20","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"98044","Ordinal":"1","Title":"bpf: Reject legacy packet loads from callbacks","CVE":"CVE-2026-98044","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"98044","Ordinal":"1","NoteData":"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.","Type":"Description","Title":"bpf: Reject legacy packet loads from callbacks"}]}}}