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CVE-2026-98547— af_packet: fix integer overflow in prb_calc_retire_blk_tmo()

Quick assessment

Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

在 Linux 内核中，以下漏洞已得到修复： af_packet：修复 prb_calc_retire_blk_tmo() 中的整数溢出问题 函数使用 32 位整数进行算术计算： 根据对验证逻辑的理解， 由用户控制，而 仅拒绝小于等于 0 的整数值或未对齐页大小的值。因此，256 MiB 的块大小可以通过验证（且 甚至为此提供了 回退机制）。 当 为 （即 256 MiB）时，乘以 8 后会发生溢出，结果为 （即 -2147483648）。若网卡报告的速率为 1 Gbps（此时除数 ），该函数最终会返回 。 触发该

AI Predicted 7.8 Difficulty: Easy

Affected Version Matrix 18

VendorProduct Version RangeStatus
Linux Linux f6fb8f100b807378fda19e83e5ac6828b638603a< 02afd75649a4e001031ed82153a5c39312ec0737 affected
f6fb8f100b807378fda19e83e5ac6828b638603a< eb5b3838b9200dac04bfe33483db0ee8287456fb affected
f6fb8f100b807378fda19e83e5ac6828b638603a< 297acc571d5813db76b147c745b91031d5f9c960 affected
f6fb8f100b807378fda19e83e5ac6828b638603a< be1aacff399d519cc48d6b34354a54dd79041140 affected
f6fb8f100b807378fda19e83e5ac6828b638603a< b2bcc6a254d6f27823a56787668ae4ee8cdb6e71 affected
f6fb8f100b807378fda19e83e5ac6828b638603a< 6279211e7d2456ecd195d236c9ee5e5c6fa5a17a affected
f6fb8f100b807378fda19e83e5ac6828b638603a< 218a944b9e035d4b47d59c69af6ca13319da15fb affected
f6fb8f100b807378fda19e83e5ac6828b638603a< 56d82862a0a243ac14ba11b6d7b57ddc2d064b95 affected
… +10 more rows
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I. Basic Information for CVE-2026-98547

Vulnerability Information
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Vulnerability Title
af_packet: fix integer overflow in prb_calc_retire_blk_tmo()
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: af_packet: fix integer overflow in prb_calc_retire_blk_tmo() prb_calc_retire_blk_tmo() computes in 32-bit int arithmetic: mbits = (blk_size_in_bytes * 8) / (1024 * 1024); If I'm reading the validation right, tp_block_size is user controlled and packet_set_ring() only rejects values that are <= 0 as int or not page aligned, so a 256MiB block goes right through (and alloc_one_pg_vec_page() even has a vzalloc fallback for it). 0x10000000 * 8 wraps to INT_MIN, and on a NIC reporting 1 Gbps (div == 1) the function ends up returning -2047. The condition is actually (8 * size) mod 2^32 >= 2^31 && div == 1, so the trigger set is [256,512), [768,1024), [1280,1536) and [1792,2048) MiB. Other sizes wrap to non-negative values and faster links divide the unsigned value back below 2^31, which is why this doesn't blow up for everyone. What makes it fatal is what happens next in init_prb_bdqc(): p1->interval_ktime = ms_to_ktime(prb_calc_retire_blk_tmo(...)); hrtimer_start(&p1->retire_blk_timer, p1->interval_ktime, HRTIMER_MODE_REL_SOFT); A negative relative timeout expires immediately. The callback unconditionally returns HRTIMER_RESTART, and hrtimer_forward() turns the negative interval into hrtimer_resolution: if (interval < hrtimer_resolution) interval = hrtimer_resolution; So the SOFT timer re-fires at the maximum rate forever, holding sk_receive_queue.lock each pass. One CPU spins in softirq until the socket is closed. Repeat with more rings and the machine is gone. The overflow itself is ancient - it was introduced together with TPACKET_V3 in f6fb8f100b80 ("af-packet: TPACKET_V3 flexible buffer implementation."). Its effect prior to f7460d2989fa ("net: af_packet: Use hrtimer to do the retire operation", v6.18) was not as clear-cut, though: the return value was stored into an unsigned short retire_blk_tov, so a negative result was truncated, and a 0-jiffy delay loop could be programmed as well. Neither is nearly as detrimental as the immediate maximum-rate spin the hrtimer conversion turned it into. (Unrelated to CVE-2019-20812 - that one was the ethtool failure path returning 0, which now returns DEFAULT_PRB_RETIRE_TOV.) Reproducer, needs CAP_NET_RAW (a --network host container has it by default) and a 1 Gbps NIC (QEMU e1000 works): int fd = socket(AF_PACKET, SOCK_RAW, htons(ETH_P_ALL)); bind(fd, ...); int v = TPACKET_V3; setsockopt(fd, SOL_PACKET, PACKET_VERSION, &v, sizeof(v)); struct tpacket_req3 req = { .tp_block_size = 0x10000000, .tp_block_nr = 1, .tp_frame_size = 2048, .tp_frame_nr = 0x10000000 / 2048, .tp_retire_blk_tov = 0, }; setsockopt(fd, SOL_PACKET, PACKET_RX_RING, &req, sizeof(req)); Compute in 64 bits instead. The operands are already bounded by the existing validation, so nothing else changes. If you'd prefer a different fix, just say so and I'll respin.
Source: CVE Program / CVE List V5
CVSS Information
N/A
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux f6fb8f100b807378fda19e83e5ac6828b638603a ~ 02afd75649a4e001031ed82153a5c39312ec0737 -
Linux Linux 3.2 -

II. Public POCs for CVE-2026-98547

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III. Intelligence Information for CVE-2026-98547

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Patches & Fixes for CVE-2026-98547 (7)

Same Patch Batch · Linux · 2026-10-18 · 436 CVEs total

CVE-2026-98583 nfc: nfcmrvl: validate helper command length before pull
CVE-2026-98570 net: ipv6: keep room for the mac header in dst_dev_overhead()
CVE-2026-98571 net: stmmac: clear stale buf->page after recycling on skb build failure
CVE-2026-98572 bpf: Fix immediate JMP JEQ/JNE on MIPS32
CVE-2026-98573 net: skbuff: fix pull-bound underflow in skb_checksum_setup_ipv6()
CVE-2026-98574 net: bcmgenet: stop Tx NAPI before disabling the queues
CVE-2026-98575 nfc: pn533: fix OOB read in pn533_acr122_is_rx_frame_valid()
CVE-2026-98576 nfc: llcp: fix slab-out-of-bounds reads when logging service names
CVE-2026-98577 nfc: llcp: fix WKS SAP hijacking via prefix match in nfc_llcp_wks_sap()
CVE-2026-98578 nfc: st21nfca: validate ISO15693 inventory length
CVE-2026-98579 nfc: llcp: fix sdreq TLV list leak on parse/alloc/send failure
CVE-2026-98580 nfc: llcp: Fix race condition in accept_queue lifecycle
CVE-2026-98581 nfc: llcp: Fix list corruption / refcount desync in nfc_llcp_recv_dm()
CVE-2026-98582 nfc: st21nfca: validate received frame size
CVE-2026-98594 tg3: clean up PHYLIB resources on probe failure
CVE-2026-98591 bpf: Fix bounds check for skb-backed dynptrs
CVE-2026-98592 net: spacemit: clear TX descriptor on fragment mapping failure
CVE-2026-98593 s390/debug: Fix NULL pointer dereference in debug_info_copy()
CVE-2026-98590 bpf: Fix bpf_sock context code generation
CVE-2026-98595 udp: remove a disconnected socket from the 4-tuple hash table

Showing top 20 of 436 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2026-98547

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