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DEBIAN-CVE-2021-47595

MediumCVSS 5.5 / 10
Published Jun 19, 2024·Last modified Jun 15, 2026
Affected Components(0)

No affected components available

Description

In the Linux kernel, the following vulnerability has been resolved: net/sched: sch_ets: don't remove idle classes from the round-robin list Shuang reported that the following script: 1) tc qdisc add dev ddd0 handle 10: parent 1: ets bands 8 strict 4 priomap 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 2) mausezahn ddd0 -A 10.10.10.1 -B 10.10.10.2 -c 0 -a own -b 00:c1:a0:c1:a0:00 -t udp & 3) tc qdisc change dev ddd0 handle 10: ets bands 4 strict 2 quanta 2500 2500 priomap 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 crashes systematically when line 2) is commented: list_del corruption, ffff8e028404bd30->next is LIST_POISON1 (dead000000000100) ------------[ cut here ]------------ kernel BUG at lib/list_debug.c:47! invalid opcode: 0000 [#1] PREEMPT SMP NOPTI CPU: 0 PID: 954 Comm: tc Not tainted 5.16.0-rc4+ #478 Hardware name: Red Hat KVM, BIOS 1.11.1-4.module+el8.1.0+4066+0f1aadab 04/01/2014 RIP: 0010:__list_del_entry_valid.cold.1+0x12/0x47 Code: fe ff 0f 0b 48 89 c1 4c 89 c6 48 c7 c7 08 42 1b 87 e8 1d c5 fe ff 0f 0b 48 89 fe 48 89 c2 48 c7 c7 98 42 1b 87 e8 09 c5 fe ff <0f> 0b 48 c7 c7 48 43 1b 87 e8 fb c4 fe ff 0f 0b 48 89 f2 48 89 fe RSP: 0018:ffffae46807a3888 EFLAGS: 00010246 RAX: 000000000000004e RBX: 0000000000000007 RCX: 0000000000000202 RDX: 0000000000000000 RSI: ffffffff871ac536 RDI: 00000000ffffffff RBP: ffffae46807a3a10 R08: 0000000000000000 R09: c0000000ffff7fff R10: 0000000000000001 R11: ffffae46807a36a8 R12: ffff8e028404b800 R13: ffff8e028404bd30 R14: dead000000000100 R15: ffff8e02fafa2400 FS: 00007efdc92e4480(0000) GS:ffff8e02fb600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000682f48 CR3: 00000001058be000 CR4: 0000000000350ef0 Call Trace: <TASK> ets_qdisc_change+0x58b/0xa70 [sch_ets] tc_modify_qdisc+0x323/0x880 rtnetlink_rcv_msg+0x169/0x4a0 netlink_rcv_skb+0x50/0x100 netlink_unicast+0x1a5/0x280 netlink_sendmsg+0x257/0x4d0 sock_sendmsg+0x5b/0x60 ____sys_sendmsg+0x1f2/0x260 ___sys_sendmsg+0x7c/0xc0 __sys_sendmsg+0x57/0xa0 do_syscall_64+0x3a/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7efdc8031338 Code: 89 02 48 c7 c0 ff ff ff ff eb b5 0f 1f 80 00 00 00 00 f3 0f 1e fa 48 8d 05 25 43 2c 00 8b 00 85 c0 75 17 b8 2e 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 58 c3 0f 1f 80 00 00 00 00 41 54 41 89 d4 55 RSP: 002b:00007ffdf1ce9828 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 0000000061b37a97 RCX: 00007efdc8031338 RDX: 0000000000000000 RSI: 00007ffdf1ce9890 RDI: 0000000000000003 RBP: 0000000000000000 R08: 0000000000000001 R09: 000000000078a940 R10: 000000000000000c R11: 0000000000000246 R12: 0000000000000001 R13: 0000000000688880 R14: 0000000000000000 R15: 0000000000000000 </TASK> Modules linked in: sch_ets sch_tbf dummy rfkill iTCO_wdt iTCO_vendor_support intel_rapl_msr intel_rapl_common joydev pcspkr i2c_i801 virtio_balloon i2c_smbus lpc_ich ip_tables xfs libcrc32c crct10dif_pclmul crc32_pclmul crc32c_intel serio_raw ghash_clmulni_intel ahci libahci libata virtio_blk virtio_console virtio_net net_failover failover sunrpc dm_mirror dm_region_hash dm_log dm_mod [last unloaded: sch_ets] ---[ end trace f35878d1912655c2 ]--- RIP: 0010:__list_del_entry_valid.cold.1+0x12/0x47 Code: fe ff 0f 0b 48 89 c1 4c 89 c6 48 c7 c7 08 42 1b 87 e8 1d c5 fe ff 0f 0b 48 89 fe 48 89 c2 48 c7 c7 98 42 1b 87 e8 09 c5 fe ff <0f> 0b 48 c7 c7 48 43 1b 87 e8 fb c4 fe ff 0f 0b 48 89 f2 48 89 fe RSP: 0018:ffffae46807a3888 EFLAGS: 00010246 RAX: 000000000000004e RBX: 0000000000000007 RCX: 0000000000000202 RDX: 0000000000000000 RSI: ffffffff871ac536 RDI: 00000000ffffffff RBP: ffffae46807a3a10 R08: 0000000000000000 R09: c0000000ffff7fff R10: 0000000000000001 R11: ffffae46807a36a8 R12: ffff8e028404b800 R13: ffff8e028404bd30 R14: dead000000000100 R15: ffff8e02fafa2400 FS: 00007efdc92e4480(0000) GS:ffff8e02fb600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000 ---truncated---

Risk Scores
Base Score
5.5

The vulnerability requires local access to the device to be exploited. It is easy for an attacker to exploit this vulnerability. An attacker needs basic access or low-level privileges. No user interaction is needed for the attacker to exploit this vulnerability. The impact is confined to the system where the vulnerability exists. There is a high impact on the availability of the system.

Threat Intelligence
5.1

Exploitation attempts have been detected. Elevated vigilance and prompt remediation are advised.

EPSS
N/A

Probability that this vulnerability will be exploited in the wild within the next 30 days.

Exploit
Not available

We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.

Related Vulnerabilities
  • CVE-2021-47595
    Upstream
  • EUVD-2021-34597
    Upstream

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Medium severity
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