{ "affected": [ { "ranges": [ { "events": [ { "introduced": "f6fb8f100b807378fda19e83e5ac6828b638603a" }, { "fixed": "02afd75649a4e001031ed82153a5c39312ec0737" }, { "fixed": "eb5b3838b9200dac04bfe33483db0ee8287456fb" }, { "fixed": "297acc571d5813db76b147c745b91031d5f9c960" }, { "fixed": "be1aacff399d519cc48d6b34354a54dd79041140" }, { "fixed": "b2bcc6a254d6f27823a56787668ae4ee8cdb6e71" }, { "fixed": "6279211e7d2456ecd195d236c9ee5e5c6fa5a17a" }, { "fixed": "218a944b9e035d4b47d59c69af6ca13319da15fb" }, { "fixed": "56d82862a0a243ac14ba11b6d7b57ddc2d064b95" } ], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "type": "GIT" } ] }, { "package": { "ecosystem": "Linux", "name": "Kernel" }, "ranges": [ { "events": [ { "introduced": "3.2.0" }, { "fixed": "5.10.271" } ], "type": "ECOSYSTEM" }, { "events": [ { "introduced": "5.11.0" }, { "fixed": "5.15.222" } ], "type": "ECOSYSTEM" }, { "events": [ { "introduced": "5.16.0" }, { "fixed": "6.1.189" } ], "type": "ECOSYSTEM" }, { "events": [ { "introduced": "6.2.0" }, { "fixed": "6.6.158" } ], "type": "ECOSYSTEM" }, { "events": [ { "introduced": "6.7.0" }, { "fixed": "6.12.112" } ], "type": "ECOSYSTEM" }, { "events": [ { "introduced": "6.13.0" }, { "fixed": "6.18.55" } ], "type": "ECOSYSTEM" }, { "events": [ { "introduced": "6.19.0" }, { "fixed": "7.2.9" } ], "type": "ECOSYSTEM" } ] } ], "database_specific": { "cna_assigner": "Linux", "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98547.json" }, "details": "In the Linux kernel, the following vulnerability has been resolved:\n\naf_packet: fix integer overflow in prb_calc_retire_blk_tmo()\n\nprb_calc_retire_blk_tmo() computes in 32-bit int arithmetic:\n\n mbits = (blk_size_in_bytes * 8) / (1024 * 1024);\n\nIf I'm reading the validation right, tp_block_size is user\ncontrolled and packet_set_ring() only rejects values that are \u003c= 0\nas int or not page aligned, so a 256MiB block goes right through\n(and alloc_one_pg_vec_page() even has a vzalloc fallback for it).\n0x10000000 * 8 wraps to INT_MIN, and on a NIC reporting 1 Gbps\n(div == 1) the function ends up returning -2047.\n\nThe condition is actually (8 * size) mod 2^32 \u003e= 2^31 \u0026\u0026 div == 1,\nso the trigger set is [256,512), [768,1024), [1280,1536) and\n[1792,2048) MiB. Other sizes wrap to non-negative values and faster\nlinks divide the unsigned value back below 2^31, which is why this\ndoesn't blow up for everyone.\n\nWhat makes it fatal is what happens next in init_prb_bdqc():\n\n p1-\u003einterval_ktime = ms_to_ktime(prb_calc_retire_blk_tmo(...));\n hrtimer_start(\u0026p1-\u003eretire_blk_timer, p1-\u003einterval_ktime,\n HRTIMER_MODE_REL_SOFT);\n\nA negative relative timeout expires immediately. The callback\nunconditionally returns HRTIMER_RESTART, and hrtimer_forward() turns\nthe negative interval into hrtimer_resolution:\n\n if (interval \u003c hrtimer_resolution)\n interval = hrtimer_resolution;\n\nSo the SOFT timer re-fires at the maximum rate forever, holding\nsk_receive_queue.lock each pass. One CPU spins in softirq until the\nsocket is closed. Repeat with more rings and the machine is gone.\n\nThe overflow itself is ancient - it was introduced together with\nTPACKET_V3 in f6fb8f100b80 (\"af-packet: TPACKET_V3 flexible buffer\nimplementation.\"). Its effect prior to f7460d2989fa (\"net:\naf_packet: Use hrtimer to do the retire operation\", v6.18) was not\nas clear-cut, though: the return value was stored into an unsigned\nshort retire_blk_tov, so a negative result was truncated, and a\n0-jiffy delay loop could be programmed as well. Neither is nearly\nas detrimental as the immediate maximum-rate spin the hrtimer\nconversion turned it into.\n\n(Unrelated to CVE-2019-20812 - that one was the ethtool failure path\nreturning 0, which now returns DEFAULT_PRB_RETIRE_TOV.)\n\nReproducer, needs CAP_NET_RAW (a --network host container has it by\ndefault) and a 1 Gbps NIC (QEMU e1000 works):\n\n int fd = socket(AF_PACKET, SOCK_RAW, htons(ETH_P_ALL));\n bind(fd, ...);\n int v = TPACKET_V3;\n setsockopt(fd, SOL_PACKET, PACKET_VERSION, \u0026v, sizeof(v));\n struct tpacket_req3 req = {\n .tp_block_size = 0x10000000,\n .tp_block_nr = 1,\n .tp_frame_size = 2048,\n .tp_frame_nr = 0x10000000 / 2048,\n .tp_retire_blk_tov = 0,\n };\n setsockopt(fd, SOL_PACKET, PACKET_RX_RING, \u0026req, sizeof(req));\n\nCompute in 64 bits instead. The operands are already bounded by the\nexisting validation, so nothing else changes. If you'd prefer a\ndifferent fix, just say so and I'll respin.", "id": "CVE-2026-98547", "modified": "2026-10-20T02:30:47.075087127Z", "published": "2026-10-18T15:18:15.669Z", "references": [ { "type": "PACKAGE", "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git" }, { "type": "WEB", "url": "https://git.kernel.org/stable/c/02afd75649a4e001031ed82153a5c39312ec0737" }, { "type": "WEB", "url": "https://git.kernel.org/stable/c/218a944b9e035d4b47d59c69af6ca13319da15fb" }, { "type": "WEB", "url": "https://git.kernel.org/stable/c/297acc571d5813db76b147c745b91031d5f9c960" }, { "type": "WEB", "url": "https://git.kernel.org/stable/c/56d82862a0a243ac14ba11b6d7b57ddc2d064b95" }, { "type": "WEB", "url": "https://git.kernel.org/stable/c/6279211e7d2456ecd195d236c9ee5e5c6fa5a17a" }, { "type": "WEB", "url": "https://git.kernel.org/stable/c/b2bcc6a254d6f27823a56787668ae4ee8cdb6e71" }, { "type": "WEB", "url": "https://git.kernel.org/stable/c/be1aacff399d519cc48d6b34354a54dd79041140" }, { "type": "WEB", "url": "https://git.kernel.org/stable/c/eb5b3838b9200dac04bfe33483db0ee8287456fb" }, { "type": "ADVISORY", "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98547.json" }, { "type": "ADVISORY", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-98547" } ], "schema_version": "1.9.0", "summary": "af_packet: fix integer overflow in prb_calc_retire_blk_tmo()" }