{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-98383","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-09-25T10:25:14.345Z","datePublished":"2026-10-09T07:34:22.408Z","dateUpdated":"2026-10-24T14:08:40.964Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-10-24T14:08:40.964Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Disallow bpf_skb_pull_data() for LWT_SEG6LOCAL\n\nAn LWT_SEG6LOCAL program can invalidate its cached SRH with\nbpf_lwt_seg6_adjust_srh() and then call bpf_skb_pull_data(). The latter\nmay reallocate skb->head, leaving the per-CPU SRH pointer dangling.\nPost-program SRH validation then writes through that pointer.\n\nDisallow bpf_skb_pull_data() for LWT_SEG6LOCAL programs so the verifier\nrejects this unsafe helper combination. Other LWT program types continue\nto expose the helper through lwt_out_func_proto()."}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - The local bpf(BPF_PROG_LOAD) path reaches check_helper_call() and the patched lwt_seg6local_func_proto(), where attacker-authored bytecode requests bpf_lwt_seg6_adjust_srh() and bpf_skb_pull_data(); an RTM_NEWROUTE then attaches it. A received SRH packet merely executes that installed program and cannot create the unsafe helper sequence.\nAC:L - The attacker controls the helper order, SRH offset and length, and can inject a large non-linear SRv6 frame so bpf_skb_pull_data() deterministically reaches __pskb_pull_tail() and pskb_expand_head(). No race is required, and repeated packets reproduce the stale-pointer write.\nPR:L - bpf_prog_load() requires CAP_BPF and CAP_NET_ADMIN for BPF_PROG_TYPE_LWT_SEG6LOCAL, but BPF_F_TOKEN_FD and bpf_token_capable() support delegating both into a user namespace; rtnetlink_rcv_msg() separately accepts CAP_NET_ADMIN in the route's network namespace. Thus a host-unprivileged token holder can perform the complete setup.\nUI:N - The attacker loads the program, installs the End.BPF route, and injects the triggering SRv6 frame without any victim action.\nS:U - The stale srh pointer and resulting corruption occur in the same host kernel that processes the attacker's BPF program and packet; no VM, IOMMU, or other security-authority boundary is crossed.\nC:H - After skb->head is freed, seg6_bpf_has_valid_srh() passes the dangling srh pointer to seg6_validate_srh(), which reads header fields and variable-length TLVs from reusable slab memory; its drop-versus-forward result also provides an observable contents oracle.\nI:H - seg6_bpf_has_valid_srh() executes srh->hdrlen = srh_state->hdrlen >> 3 through the dangling pointer, producing an attacker-valued one-byte write into freed slab memory that can corrupt a reclaimed object or allocator state and support control-flow compromise.\nA:H - The stale write in seg6_bpf_has_valid_srh() is a confirmed slab use-after-free and can trigger a KASAN panic or later kernel oops through corrupted freed-object state; the attacker can repeat it with additional packets."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/core/filter.c"],"versions":[{"version":"004d4b274e2a1a895a0e5dc66158b90a7d463d44","lessThan":"0f38472a2aa8704a6b514c0dfa9c32f3672b8f32","status":"affected","versionType":"git"},{"version":"004d4b274e2a1a895a0e5dc66158b90a7d463d44","lessThan":"cae8674489f26edf7553fdd660599466cbb4c32f","status":"affected","versionType":"git"},{"version":"004d4b274e2a1a895a0e5dc66158b90a7d463d44","lessThan":"9f9e57b5a3a033f95f49ef9d541340cdbcb80abb","status":"affected","versionType":"git"},{"version":"004d4b274e2a1a895a0e5dc66158b90a7d463d44","lessThan":"df0072be6fc373cb22f9ea854d458b04e32a03cf","status":"affected","versionType":"git"},{"version":"004d4b274e2a1a895a0e5dc66158b90a7d463d44","lessThan":"b9bb0e735460751b620156f800a4279a28573392","status":"affected","versionType":"git"},{"version":"004d4b274e2a1a895a0e5dc66158b90a7d463d44","lessThan":"37b18688cd18fd86d2f35c212df1611862a26cd5","status":"affected","versionType":"git"},{"version":"004d4b274e2a1a895a0e5dc66158b90a7d463d44","lessThan":"fca71ead7a20290af1e2046983eeafae43d21af1","status":"affected","versionType":"git"},{"version":"004d4b274e2a1a895a0e5dc66158b90a7d463d44","lessThan":"e4a62833adff6ef0fe7c0b90393204fe3c26b5c5","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/core/filter.c"],"versions":[{"version":"4.18","status":"affected"},{"version":"0","lessThan":"4.18","status":"unaffected","versionType":"semver"},{"version":"5.10.271","lessThanOrEqual":"5.10.*","status":"unaffected","versionType":"semver"},{"version":"5.15.222","lessThanOrEqual":"5.15.*","status":"unaffected","versionType":"semver"},{"version":"6.1.189","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.6.158","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.112","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.55","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.2.9","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":"4.18","versionEndExcluding":"5.10.271"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.18","versionEndExcluding":"5.15.222"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.18","versionEndExcluding":"6.1.189"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.18","versionEndExcluding":"6.6.158"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.18","versionEndExcluding":"6.12.112"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.18","versionEndExcluding":"6.18.55"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.18","versionEndExcluding":"7.2.9"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.18","versionEndExcluding":"7.3"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/0f38472a2aa8704a6b514c0dfa9c32f3672b8f32"},{"url":"https://git.kernel.org/stable/c/cae8674489f26edf7553fdd660599466cbb4c32f"},{"url":"https://git.kernel.org/stable/c/9f9e57b5a3a033f95f49ef9d541340cdbcb80abb"},{"url":"https://git.kernel.org/stable/c/df0072be6fc373cb22f9ea854d458b04e32a03cf"},{"url":"https://git.kernel.org/stable/c/b9bb0e735460751b620156f800a4279a28573392"},{"url":"https://git.kernel.org/stable/c/37b18688cd18fd86d2f35c212df1611862a26cd5"},{"url":"https://git.kernel.org/stable/c/fca71ead7a20290af1e2046983eeafae43d21af1"},{"url":"https://git.kernel.org/stable/c/e4a62833adff6ef0fe7c0b90393204fe3c26b5c5"}],"title":"bpf: Disallow bpf_skb_pull_data() for LWT_SEG6LOCAL","x_generator":{"engine":"bippy-1.2.0"}}}}