CVE-2021-47562

CVE-2021-47562 is a medium-severity vulnerability in Linux Linux Kernel with a CVSS 3.x base score of 5.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-476.

Key facts

Description

In the Linux kernel, the following vulnerability has been resolved: ice: fix vsi->txq_map sizing The approach of having XDP queue per CPU regardless of user's setting exposed a hidden bug that could occur in case when Rx queue count differ from Tx queue count. Currently vsi->txq_map's size is equal to the doubled vsi->alloc_txq, which is not correct due to the fact that XDP rings were previously based on the Rx queue count. Below splat can be seen when ethtool -L is used and XDP rings are configured: [ 682.875339] BUG: kernel NULL pointer dereference, address: 000000000000000f [ 682.883403] #PF: supervisor read access in kernel mode [ 682.889345] #PF: error_code(0x0000) - not-present page [ 682.895289] PGD 0 P4D 0 [ 682.898218] Oops: 0000 [#1] PREEMPT SMP PTI [ 682.903055] CPU: 42 PID: 2878 Comm: ethtool Tainted: G OE 5.15.0-rc5+ #1 [ 682.912214] Hardware name: Intel Corp. GRANTLEY/GRANTLEY, BIOS GRRFCRB1.86B.0276.D07.1605190235 05/19/2016 [ 682.923380] RIP: 0010:devres_remove+0x44/0x130 [ 682.928527] Code: 49 89 f4 55 48 89 fd 4c 89 ff 53 48 83 ec 10 e8 92 b9 49 00 48 8b 9d a8 02 00 00 48 8d 8d a0 02 00 00 49 89 c2 48 39 cb 74 0f <4c> 3b 63 10 74 25 48 8b 5b 08 48 39 cb 75 f1 4c 89 ff 4c 89 d6 e8 [ 682.950237] RSP: 0018:ffffc90006a679f0 EFLAGS: 00010002 [ 682.956285] RAX: 0000000000000286 RBX: ffffffffffffffff RCX: ffff88908343a370 [ 682.964538] RDX: 0000000000000001 RSI: ffffffff81690d60 RDI: 0000000000000000 [ 682.972789] RBP: ffff88908343a0d0 R08: 0000000000000000 R09: 0000000000000000 [ 682.981040] R10: 0000000000000286 R11: 3fffffffffffffff R12: ffffffff81690d60 [ 682.989282] R13: ffffffff81690a00 R14: ffff8890819807a8 R15: ffff88908343a36c [ 682.997535] FS: 00007f08c7bfa740(0000) GS:ffff88a03fd00000(0000) knlGS:0000000000000000 [ 683.006910] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 683.013557] CR2: 000000000000000f CR3: 0000001080a66003 CR4: 00000000003706e0 [ 683.021819] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 683.030075] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 683.038336] Call Trace: [ 683.041167] devm_kfree+0x33/0x50 [ 683.045004] ice_vsi_free_arrays+0x5e/0xc0 [ice] [ 683.050380] ice_vsi_rebuild+0x4c8/0x750 [ice] [ 683.055543] ice_vsi_recfg_qs+0x9a/0x110 [ice] [ 683.060697] ice_set_channels+0x14f/0x290 [ice] [ 683.065962] ethnl_set_channels+0x333/0x3f0 [ 683.070807] genl_family_rcv_msg_doit+0xea/0x150 [ 683.076152] genl_rcv_msg+0xde/0x1d0 [ 683.080289] ? channels_prepare_data+0x60/0x60 [ 683.085432] ? genl_get_cmd+0xd0/0xd0 [ 683.089667] netlink_rcv_skb+0x50/0xf0 [ 683.094006] genl_rcv+0x24/0x40 [ 683.097638] netlink_unicast+0x239/0x340 [ 683.102177] netlink_sendmsg+0x22e/0x470 [ 683.106717] sock_sendmsg+0x5e/0x60 [ 683.110756] __sys_sendto+0xee/0x150 [ 683.114894] ? handle_mm_fault+0xd0/0x2a0 [ 683.119535] ? do_user_addr_fault+0x1f3/0x690 [ 683.134173] __x64_sys_sendto+0x25/0x30 [ 683.148231] do_syscall_64+0x3b/0xc0 [ 683.161992] entry_SYSCALL_64_after_hwframe+0x44/0xae Fix this by taking into account the value that num_possible_cpus() yields in addition to vsi->alloc_txq instead of doubling the latter.

Frequently asked questions

What is CVE-2021-47562?
In the Linux kernel, the following vulnerability has been resolved: ice: fix vsi->txq_map sizing The approach of having XDP queue per CPU regardless of user's setting exposed a hidden bug that could occur in case when Rx queue count differ from Tx queue count. Currently vsi->txq_map's size is equal to the doubled vsi->alloc_txq, which is not correct due to the fact that XDP rings were previously based on the Rx queue count. Below splat can be seen when ethtool -L is used and XDP rings are configured: [ 682.875339] BUG: kernel NULL pointer dereference, address: 000000000000000f [ 682.883403] #PF: supervisor read access in kernel mode [ 682.889345] #PF: error_code(0x0000) - not-present page [ 682.895289] PGD 0 P4D 0 [ 682.898218] Oops: 0000 [#1] PREEMPT SMP PTI [ 682.903055] CPU: 42 PID: 2878 Comm: ethtool Tainted: G OE 5.15.0-rc5+ #1 [ 682.912214] Hardware name: Intel Corp. GRANTLEY/GRANTLEY, BIOS GRRFCRB1.86B.0276.D07.1605190235 05/19/2016 [ 682.923380] RIP: 0010:devres_remove+0x44/0x130 [ 682.928527] Code: 49 89 f4 55 48 89 fd 4c 89 ff 53 48 83 ec 10 e8 92 b9 49 00 48 8b 9d a8 02 00 00 48 8d 8d a0 02 00 00 49 89 c2 48 39 cb 74 0f <4c> 3b 63 10 74 25 48 8b 5b 08 48 39 cb 75 f1 4c 89 ff 4c 89 d6 e8 [ 682.950237] RSP: 0018:ffffc90006a679f0 EFLAGS: 00010002 [ 682.956285] RAX: 0000000000000286 RBX: ffffffffffffffff RCX: ffff88908343a370 [ 682.964538] RDX: 0000000000000001 RSI: ffffffff81690d60 RDI: 0000000000000000 [ 682.972789] RBP: ffff88908343a0d0 R08: 0000000000000000 R09: 0000000000000000 [ 682.981040] R10: 0000000000000286 R11: 3fffffffffffffff R12: ffffffff81690d60 [ 682.989282] R13: ffffffff81690a00 R14: ffff8890819807a8 R15: ffff88908343a36c [ 682.997535] FS: 00007f08c7bfa740(0000) GS:ffff88a03fd00000(0000) knlGS:0000000000000000 [ 683.006910] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 683.013557] CR2: 000000000000000f CR3: 0000001080a66003 CR4: 00000000003706e0 [ 683.021819] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 683.030075] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 683.038336] Call Trace: [ 683.041167] devm_kfree+0x33/0x50 [ 683.045004] ice_vsi_free_arrays+0x5e/0xc0 [ice] [ 683.050380] ice_vsi_rebuild+0x4c8/0x750 [ice] [ 683.055543] ice_vsi_recfg_qs+0x9a/0x110 [ice] [ 683.060697] ice_set_channels+0x14f/0x290 [ice] [ 683.065962] ethnl_set_channels+0x333/0x3f0 [ 683.070807] genl_family_rcv_msg_doit+0xea/0x150 [ 683.076152] genl_rcv_msg+0xde/0x1d0 [ 683.080289] ? channels_prepare_data+0x60/0x60 [ 683.085432] ? genl_get_cmd+0xd0/0xd0 [ 683.089667] netlink_rcv_skb+0x50/0xf0 [ 683.094006] genl_rcv+0x24/0x40 [ 683.097638] netlink_unicast+0x239/0x340 [ 683.102177] netlink_sendmsg+0x22e/0x470 [ 683.106717] sock_sendmsg+0x5e/0x60 [ 683.110756] __sys_sendto+0xee/0x150 [ 683.114894] ? handle_mm_fault+0xd0/0x2a0 [ 683.119535] ? do_user_addr_fault+0x1f3/0x690 [ 683.134173] __x64_sys_sendto+0x25/0x30 [ 683.148231] do_syscall_64+0x3b/0xc0 [ 683.161992] entry_SYSCALL_64_after_hwframe+0x44/0xae Fix this by taking into account the value that num_possible_cpus() yields in addition to vsi->alloc_txq instead of doubling the latter.
How severe is CVE-2021-47562?
CVE-2021-47562 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2021-47562 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (11th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-47562?
CVE-2021-47562 primarily affects Linux Linux Kernel. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-47562?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2021-47562 have an EU (EUVD) identifier?
Yes. CVE-2021-47562 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2021-34564.
When was CVE-2021-47562 published?
CVE-2021-47562 was published on 2024-05-24 and last updated on 2026-06-17.

References

Affected products (3)

More vulnerabilities in Linux Linux Kernel

All CVEs affecting Linux Linux Kernel →

Other CWE-476 (NULL Pointer Dereference) vulnerabilities

Browse all CWE-476 (NULL Pointer Dereference) vulnerabilities →