{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2025-40079", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-04-16T07:20:57.160Z", "datePublished": "2025-10-28T11:48:44.122Z", "dateUpdated": "2026-08-05T12:07:35.719Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:07:35.719Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nriscv, bpf: Sign extend struct ops return values properly\n\nThe ns_bpf_qdisc selftest triggers a kernel panic:\n\n Unable to handle kernel paging request at virtual address ffffffffa38dbf58\n Current test_progs pgtable: 4K pagesize, 57-bit VAs, pgdp=0x00000001109cc000\n [ffffffffa38dbf58] pgd=000000011fffd801, p4d=000000011fffd401, pud=000000011fffd001, pmd=0000000000000000\n Oops [#1]\n Modules linked in: bpf_testmod(OE) xt_conntrack nls_iso8859_1 [...] [last unloaded: bpf_testmod(OE)]\n CPU: 1 UID: 0 PID: 23584 Comm: test_progs Tainted: G W OE 6.17.0-rc1-g2465bb83e0b4 #1 NONE\n Tainted: [W]=WARN, [O]=OOT_MODULE, [E]=UNSIGNED_MODULE\n Hardware name: Unknown Unknown Product/Unknown Product, BIOS 2024.01+dfsg-1ubuntu5.1 01/01/2024\n epc : __qdisc_run+0x82/0x6f0\n ra : __qdisc_run+0x6e/0x6f0\n epc : ffffffff80bd5c7a ra : ffffffff80bd5c66 sp : ff2000000eecb550\n gp : ffffffff82472098 tp : ff60000096895940 t0 : ffffffff8001f180\n t1 : ffffffff801e1664 t2 : 0000000000000000 s0 : ff2000000eecb5d0\n s1 : ff60000093a6a600 a0 : ffffffffa38dbee8 a1 : 0000000000000001\n a2 : ff2000000eecb510 a3 : 0000000000000001 a4 : 0000000000000000\n a5 : 0000000000000010 a6 : 0000000000000000 a7 : 0000000000735049\n s2 : ffffffffa38dbee8 s3 : 0000000000000040 s4 : ff6000008bcda000\n s5 : 0000000000000008 s6 : ff60000093a6a680 s7 : ff60000093a6a6f0\n s8 : ff60000093a6a6ac s9 : ff60000093140000 s10: 0000000000000000\n s11: ff2000000eecb9d0 t3 : 0000000000000000 t4 : 0000000000ff0000\n t5 : 0000000000000000 t6 : ff60000093a6a8b6\n status: 0000000200000120 badaddr: ffffffffa38dbf58 cause: 000000000000000d\n [] __qdisc_run+0x82/0x6f0\n [] __dev_queue_xmit+0x4c0/0x1128\n [] neigh_resolve_output+0xd0/0x170\n [] ip6_finish_output2+0x226/0x6c8\n [] ip6_finish_output+0x10c/0x2a0\n [] ip6_output+0x5e/0x178\n [] ip6_xmit+0x29a/0x608\n [] inet6_csk_xmit+0xe6/0x140\n [] __tcp_transmit_skb+0x45c/0xaa8\n [] tcp_connect+0x9ce/0xd10\n [] tcp_v6_connect+0x4ac/0x5e8\n [] __inet_stream_connect+0xd8/0x318\n [] inet_stream_connect+0x3e/0x68\n [] __sys_connect_file+0x50/0x88\n [] __sys_connect+0x96/0xc8\n [] __riscv_sys_connect+0x20/0x30\n [] do_trap_ecall_u+0x256/0x378\n [] handle_exception+0x14a/0x156\n Code: 892a 0363 1205 489c 8bc1 c7e5 2d03 084a 2703 080a (2783) 0709\n ---[ end trace 0000000000000000 ]---\n\nThe bpf_fifo_dequeue prog returns a skb which is a pointer. The pointer\nis treated as a 32bit value and sign extend to 64bit in epilogue. This\nbehavior is right for most bpf prog types but wrong for struct ops which\nrequires RISC-V ABI.\n\nSo let's sign extend struct ops return values according to the function\nmodel and RISC-V ABI([0]).\n\n [0]: https://riscv.org/wp-content/uploads/2024/12/riscv-calling.pdf" } ], "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 vulnerable code is the RISC-V BPF JIT struct_ops trampoline, reached by loading/attaching a BPF struct_ops program via the bpf() syscall and triggered by local syscalls (the reported oops comes from connect()). Per kernel guidance BPF is Local.\nAC:L - The miscompilation is deterministic — every invocation of a struct_ops callback with an 8-byte return type truncates the value; no race, timing window, or condition outside the attacker's control is involved, and heap grooming lets the attacker influence which address the truncated pointer resolves to.\nPR:L - Attaching a struct_ops program needs CAP_BPF, which is delegable to unprivileged container workloads via BPF tokens; and on a system already running a BPF qdisc or struct_ops scheduler, any unprivileged local user's ordinary network traffic drives the miscompiled callback, so real root in the init namespace is not required.\nUI:N - The corrupted return value is consumed by the kernel's own packet-transmit path as soon as the attacker sends traffic; no action by any other user is needed.\nS:U - The truncated pointer is dereferenced by kernel code within the same kernel security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - The truncated pointer resolves into the mapped kernel-image window and is then treated as a struct sk_buff by sch_direct_xmit(), so kernel image/global memory is read through the confused object and can even be handed to the NIC for transmission — a type confusion yielding kernel memory disclosure.\nI:H - The packet path writes through the confused pointer (skb list linkage, requeue, stats updates) into whatever writable kernel .data/.bss lands at the sign-extended address, giving a type-confusion write primitive against kernel state.\nA:H - The commit documents a reproducible kernel oops (\"Unable to handle kernel paging request at virtual address ffffffffa38dbf58\" in __qdisc_run) taking down the machine, repeatable by an unprivileged process." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "arch/riscv/net/bpf_jit_comp64.c" ], "versions": [ { "version": "25ad10658dc1068a671553ff10e19a812c2a3783", "lessThan": "92751937f12a7d34ad492577a251c94a55e97e72", "status": "affected", "versionType": "git" }, { "version": "25ad10658dc1068a671553ff10e19a812c2a3783", "lessThan": "918a399501e28e0cc36dbd1fcfb4208f8aa1e4d1", "status": "affected", "versionType": "git" }, { "version": "25ad10658dc1068a671553ff10e19a812c2a3783", "lessThan": "fd2e08128944a7679e753f920e9eda72057e427c", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "arch/riscv/net/bpf_jit_comp64.c" ], "versions": [ { "version": "6.6", "status": "affected" }, { "version": "0", "lessThan": "6.6", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.53", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.17.3", "lessThanOrEqual": "6.17.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18", "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": "6.6", "versionEndExcluding": "6.12.53" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.6", "versionEndExcluding": "6.17.3" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.6", "versionEndExcluding": "6.18" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/92751937f12a7d34ad492577a251c94a55e97e72" }, { "url": "https://git.kernel.org/stable/c/918a399501e28e0cc36dbd1fcfb4208f8aa1e4d1" }, { "url": "https://git.kernel.org/stable/c/fd2e08128944a7679e753f920e9eda72057e427c" } ], "title": "riscv, bpf: Sign extend struct ops return values properly", "x_generator": { "engine": "bippy-1.2.0" } } } }