{"cve":"CVE-2021-46947","nvd":{"published":"2024-02-27T19:04:06.283","modified":"2026-06-17T04:15:56.670","status":"Modified","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nsfc: adjust efx->xdp_tx_queue_count with the real number of initialized queues\n\nefx->xdp_tx_queue_count is initially initialized to num_possible_cpus() and is\nlater used to allocate and traverse efx->xdp_tx_queues lookup array. However,\nwe may end up not initializing all the array slots with real queues during\nprobing. This results, for example, in a NULL pointer dereference, when running\n\"# ethtool -S <iface>\", similar to below\n\n[2570283.664955][T4126959] BUG: kernel NULL pointer dereference, address: 00000000000000f8\n[2570283.681283][T4126959] #PF: supervisor read access in kernel mode\n[2570283.695678][T4126959] #PF: error_code(0x0000) - not-present page\n[2570283.710013][T4126959] PGD 0 P4D 0\n[2570283.721649][T4126959] Oops: 0000 [#1] SMP PTI\n[2570283.734108][T4126959] CPU: 23 PID: 4126959 Comm: ethtool Tainted: G           O      5.10.20-cloudflare-2021.3.1 #1\n[2570283.752641][T4126959] Hardware name: <redacted>\n[2570283.781408][T4126959] RIP: 0010:efx_ethtool_get_stats+0x2ca/0x330 [sfc]\n[2570283.796073][T4126959] Code: 00 85 c0 74 39 48 8b 95 a8 0f 00 00 48 85 d2 74 2d 31 c0 eb 07 48 8b 95 a8 0f 00 00 48 63 c8 49 83 c4 08 83 c0 01 48 8b 14 ca <48> 8b 92 f8 00 00 00 49 89 54 24 f8 39 85 a0 0f 00 00 77 d7 48 8b\n[2570283.831259][T4126959] RSP: 0018:ffffb79a77657ce8 EFLAGS: 00010202\n[2570283.845121][T4126959] RAX: 0000000000000019 RBX: ffffb799cd0c9280 RCX: 0000000000000018\n[2570283.860872][T4126959] RDX: 0000000000000000 RSI: ffff96dd970ce000 RDI: 0000000000000005\n[2570283.876525][T4126959] RBP: ffff96dd86f0a000 R08: ffff96dd970ce480 R09: 000000000000005f\n[2570283.892014][T4126959] R10: ffffb799cd0c9fff R11: ffffb799cd0c9000 R12: ffffb799cd0c94f8\n[2570283.907406][T4126959] R13: ffffffffc11b1090 R14: ffff96dd970ce000 R15: ffffffffc11cd66c\n[2570283.922705][T4126959] FS:  00007fa7723f8740(0000) GS:ffff96f51fac0000(0000) knlGS:0000000000000000\n[2570283.938848][T4126959] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n[2570283.952524][T4126959] CR2: 00000000000000f8 CR3: 0000001a73e6e006 CR4: 00000000007706e0\n[2570283.967529][T4126959] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000\n[2570283.982400][T4126959] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400\n[2570283.997308][T4126959] PKRU: 55555554\n[2570284.007649][T4126959] Call Trace:\n[2570284.017598][T4126959]  dev_ethtool+0x1832/0x2830\n\nFix this by adjusting efx->xdp_tx_queue_count after probing to reflect the true\nvalue of initialized slots in efx->xdp_tx_queues.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","score":5.5},"cwes":["CWE-476"],"references":["https://git.kernel.org/stable/c/99ba0ea616aabdc8e26259fd722503e012199a76","https://git.kernel.org/stable/c/ebeac958b690123a0b40aa61f688f2f170035fad","https://git.kernel.org/stable/c/99ba0ea616aabdc8e26259fd722503e012199a76","https://git.kernel.org/stable/c/ebeac958b690123a0b40aa61f688f2f170035fad"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T21:45:59.823092188+00:00"},"epss":{"cve":"CVE-2021-46947","score":0.00195,"percentile":0.09213,"date":"2026-11-01"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}