{"schema":"threatline.record/2","record":{"id":"CVE-2026-98044","aliases":[],"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.","categories":["Operating systems"],"product":"Linux","vendor":"Linux","ecosystem":null,"affected_ranges":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98044","source_modified_at":"2026-10-21T12:54:12.833Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"Linux","vendor":"Linux","versions":[{"version":"8674e2db06cff6b50f2216eed9a761d15425bb34","lessThan":"cebda2a2bb4183550eae9dcf888c16407b4fffda","status":"affected","versionType":"git"},{"version":"ce01a4e5cfac7adbe0be565f90cd32ecbb2f8337","lessThan":"3484a99303912db62428494a9061212049027e57","status":"affected","versionType":"git"},{"version":"ee861486e377edc55361c08dcbceab3f6b6577bd","lessThan":"bc489c0c9b8c86bd7fac42cfd1bb152f042fca56","status":"affected","versionType":"git"},{"version":"ee861486e377edc55361c08dcbceab3f6b6577bd","lessThan":"e7d28823c662128caae63f14e16bd394916c139b","status":"affected","versionType":"git"},{"version":"928d354ae3557e8f755a227e67be88034eb3cd7f","status":"affected","versionType":"git"},{"version":"8a800497d9f6c2ec9c2c1ba7b71d0ac2ea7f7bbe","status":"affected","versionType":"git"},{"version":"de1055e7f9e67af32b1f3376066272b04e5223c0","status":"affected","versionType":"git"},{"version":"37ad2bb11e9de92cb7b94548705eeedd87f7d392","status":"affected","versionType":"git"},{"version":"d846d83bdacbd8f14fc45c63b8c1d22608452e1c","status":"affected","versionType":"git"},{"version":"6.12.101","lessThan":"6.12.114","status":"affected","versionType":"semver"},{"version":"6.18.42","lessThan":"6.18.53","status":"affected","versionType":"semver"},{"version":"5.10.265","lessThan":"5.11","status":"affected","versionType":"semver"},{"version":"5.15.216","lessThan":"5.16","status":"affected","versionType":"semver"},{"version":"6.1.183","lessThan":"6.2","status":"affected","versionType":"semver"},{"version":"6.6.148","lessThan":"6.7","status":"affected","versionType":"semver"},{"version":"7.0.10","lessThan":"7.1","status":"affected","versionType":"semver"}],"defaultStatus":"unaffected"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98044","source_modified_at":"2026-10-21T12:54:12.833Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"Linux","vendor":"Linux","versions":[{"version":"7.1","status":"affected"},{"version":"0","lessThan":"7.1","status":"unaffected","versionType":"semver"},{"version":"6.12.114","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.53","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"}],"defaultStatus":"affected"}],"fixed_versions":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98044","source_modified_at":"2026-10-21T12:54:12.833Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"3484a99303912db62428494a9061212049027e57","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98044","source_modified_at":"2026-10-21T12:54:12.833Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"6.12.114","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98044","source_modified_at":"2026-10-21T12:54:12.833Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"6.18.53","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98044","source_modified_at":"2026-10-21T12:54:12.833Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"5.11","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98044","source_modified_at":"2026-10-21T12:54:12.833Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"5.16","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98044","source_modified_at":"2026-10-21T12:54:12.833Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"6.2","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98044","source_modified_at":"2026-10-21T12:54:12.833Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"6.7","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98044","source_modified_at":"2026-10-21T12:54:12.833Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"7.1","basis":"first unaffected version stated in the CVE record"}],"cvss":null,"severity":null,"kev":{"listed":false},"epss":{"probability":0.00168,"percentile":0.05757,"score_date":"2026-10-23"},"published_at":"2026-09-25T10:23:55.454Z","modified_at":"2026-10-21T12:54:12.833Z","provenance":[{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-98044","fetched_at":"2026-10-23T18:45:31.882637Z","source_modified_at":"2026-10-21T12:54:12.833Z"},{"source":"EPSS","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-98044","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-23"}],"sources":["CVE List","EPSS"],"references":[{"source":"CVE List","url":"https://git.kernel.org/stable/c/cebda2a2bb4183550eae9dcf888c16407b4fffda"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/3484a99303912db62428494a9061212049027e57"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/bc489c0c9b8c86bd7fac42cfd1bb152f042fca56"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/e7d28823c662128caae63f14e16bd394916c139b"}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"cve_state":"PUBLISHED","classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":"product","confidence":"heuristic","reviewed":false},"change_timestamp":"2026-10-21T12:54:12.833Z","content_hash":"cb61059be6d6d35ae5d02c4f1cbf31c55c3b5d913743d497dc1e7224bae3a6d1"}}