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CVE-2021-47451— netfilter: xt_IDLETIMER: fix panic that occurs when timer_type has garbage value

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.

Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于当timer_type具有垃圾值时会发生恐慌。

CVSS 7.8 · High EPSS 0.24% · P14

Possible ATT&CK Techniques 1 AI

T1068 · Exploitation for Privilege Escalation

Affected Version Matrix 8

VendorProduct Version RangeStatus
Linux Linux 68983a354a655c35d3fb204489d383a2a051fda7< 2a670c323055282c9b72794a491d53cef86bbeaf affected
68983a354a655c35d3fb204489d383a2a051fda7< cae7cab804c943d723d52724a3aeb07a3f4a2650 affected
68983a354a655c35d3fb204489d383a2a051fda7< 902c0b1887522a099aa4e1e6b4b476c2fe5dd13e affected
5.7 affected
< 5.7 unaffected
5.10.76≤ 5.10.* unaffected
5.14.15≤ 5.14.* unaffected
5.15≤ * unaffected
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I. Basic Information for CVE-2021-47451

Vulnerability Information
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Vulnerability Title
netfilter: xt_IDLETIMER: fix panic that occurs when timer_type has garbage value
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: netfilter: xt_IDLETIMER: fix panic that occurs when timer_type has garbage value Currently, when the rule related to IDLETIMER is added, idletimer_tg timer structure is initialized by kmalloc on executing idletimer_tg_create function. However, in this process timer->timer_type is not defined to a specific value. Thus, timer->timer_type has garbage value and it occurs kernel panic. So, this commit fixes the panic by initializing timer->timer_type using kzalloc instead of kmalloc. Test commands: # iptables -A OUTPUT -j IDLETIMER --timeout 1 --label test $ cat /sys/class/xt_idletimer/timers/test Killed Splat looks like: BUG: KASAN: user-memory-access in alarm_expires_remaining+0x49/0x70 Read of size 8 at addr 0000002e8c7bc4c8 by task cat/917 CPU: 12 PID: 917 Comm: cat Not tainted 5.14.0+ #3 79940a339f71eb14fc81aee1757a20d5bf13eb0e Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-1ubuntu1.1 04/01/2014 Call Trace: dump_stack_lvl+0x6e/0x9c kasan_report.cold+0x112/0x117 ? alarm_expires_remaining+0x49/0x70 __asan_load8+0x86/0xb0 alarm_expires_remaining+0x49/0x70 idletimer_tg_show+0xe5/0x19b [xt_IDLETIMER 11219304af9316a21bee5ba9d58f76a6b9bccc6d] dev_attr_show+0x3c/0x60 sysfs_kf_seq_show+0x11d/0x1f0 ? device_remove_bin_file+0x20/0x20 kernfs_seq_show+0xa4/0xb0 seq_read_iter+0x29c/0x750 kernfs_fop_read_iter+0x25a/0x2c0 ? __fsnotify_parent+0x3d1/0x570 ? iov_iter_init+0x70/0x90 new_sync_read+0x2a7/0x3d0 ? __x64_sys_llseek+0x230/0x230 ? rw_verify_area+0x81/0x150 vfs_read+0x17b/0x240 ksys_read+0xd9/0x180 ? vfs_write+0x460/0x460 ? do_syscall_64+0x16/0xc0 ? lockdep_hardirqs_on+0x79/0x120 __x64_sys_read+0x43/0x50 do_syscall_64+0x3b/0xc0 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f0cdc819142 Code: c0 e9 c2 fe ff ff 50 48 8d 3d 3a ca 0a 00 e8 f5 19 02 00 0f 1f 44 00 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 0f 05 <48> 3d 00 f0 ff ff 77 56 c3 0f 1f 44 00 00 48 83 ec 28 48 89 54 24 RSP: 002b:00007fff28eee5b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 0000000000020000 RCX: 00007f0cdc819142 RDX: 0000000000020000 RSI: 00007f0cdc032000 RDI: 0000000000000003 RBP: 00007f0cdc032000 R08: 00007f0cdc031010 R09: 0000000000000000 R10: 0000000000000022 R11: 0000000000000246 R12: 00005607e9ee31f0 R13: 0000000000000003 R14: 0000000000020000 R15: 0000000000020000
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
Vulnerability Title
Linux kernel 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于当timer_type具有垃圾值时会发生恐慌。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux 68983a354a655c35d3fb204489d383a2a051fda7 ~ 2a670c323055282c9b72794a491d53cef86bbeaf -
Linux Linux 5.7 -

II. Public POCs for CVE-2021-47451

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III. Intelligence Information for CVE-2021-47451

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Other References for CVE-2021-47451 (3)

Same Patch Batch · Linux · 2024-05-22 · 63 CVEs total

CVE-2021-47496 9.8 CRITICAL net/tls: Fix flipped sign in tls_err_abort() calls
CVE-2021-47478 9.1 CRITICAL isofs: Fix out of bound access for corrupted isofs image
CVE-2021-47450 8.8 HIGH KVM: arm64: Fix host stage-2 PGD refcount
CVE-2021-47433 8.1 HIGH btrfs: fix abort logic in btrfs_replace_file_extents
CVE-2021-47485 7.8 HIGH IB/qib: Protect from buffer overflow in struct qib_user_sdma_pkt fields
CVE-2021-47446 7.8 HIGH drm/msm/a4xx: fix error handling in a4xx_gpu_init()
CVE-2021-47447 7.8 HIGH drm/msm/a3xx: fix error handling in a3xx_gpu_init()
CVE-2021-47492 7.8 HIGH mm, thp: bail out early in collapse_file for writeback page
CVE-2021-47493 7.8 HIGH ocfs2: fix race between searching chunks and release journal_head from buffer_head
CVE-2021-47494 7.8 HIGH cfg80211: fix management registrations locking
CVE-2021-47483 7.8 HIGH regmap: Fix possible double-free in regcache_rbtree_exit()
CVE-2021-47461 7.8 HIGH userfaultfd: fix a race between writeprotect and exit_mmap()
CVE-2021-47459 7.8 HIGH can: j1939: j1939_netdev_start(): fix UAF for rx_kref of j1939_priv
CVE-2021-47448 7.5 HIGH mptcp: fix possible stall on recvmsg()
CVE-2021-47458 7.1 HIGH ocfs2: mount fails with buffer overflow in strlen
CVE-2021-47465 7.1 HIGH KVM: PPC: Book3S HV: Fix stack handling in idle_kvm_start_guest()
CVE-2021-47438 7.1 HIGH net/mlx5e: Fix memory leak in mlx5_core_destroy_cq() error path
CVE-2024-36010 igb: Fix string truncation warnings in igb_set_fw_version
CVE-2021-47473 scsi: qla2xxx: Fix a memory leak in an error path of qla2x00_process_els()
CVE-2021-47474 comedi: vmk80xx: fix bulk-buffer overflow

Showing top 20 of 63 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

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