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CVE-2021-47126— ipv6: Fix KASAN: slab-out-of-bounds Read in fib6_nh_flush_exceptions

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 ipv6 模块的 fib6_nh_flush_exceptions 方法中存在错误。

CVSS 7.8 · High EPSS 0.25% · P15

Possible ATT&CK Techniques 1 AI

T1059 · Command and Scripting Interpreter

Affected Version Matrix 10

VendorProduct Version RangeStatus
Linux Linux f88d8ea67fbdbac7a64bfa6ed9a2ba27bb822f74< 7ba7fa78a92dc410b6f93ed73075ab669c3a0b59 affected
f88d8ea67fbdbac7a64bfa6ed9a2ba27bb822f74< 09870235827451409ff546b073d754a19fd17e2e affected
f88d8ea67fbdbac7a64bfa6ed9a2ba27bb822f74< 0a462e25ef0f7ab305081a08d435bbd1f13c0a94 affected
f88d8ea67fbdbac7a64bfa6ed9a2ba27bb822f74< 821bbf79fe46a8b1d18aa456e8ed0a3c208c3754 affected
5.3 affected
< 5.3 unaffected
5.4.125≤ 5.4.* unaffected
5.10.43≤ 5.10.* unaffected
… +2 more rows
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I. Basic Information for CVE-2021-47126

Vulnerability Information
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Vulnerability Title
ipv6: Fix KASAN: slab-out-of-bounds Read in fib6_nh_flush_exceptions
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: ipv6: Fix KASAN: slab-out-of-bounds Read in fib6_nh_flush_exceptions Reported by syzbot: HEAD commit: 90c911ad Merge tag 'fixes' of git://git.kernel.org/pub/scm.. git tree: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master dashboard link: https://syzkaller.appspot.com/bug?extid=123aa35098fd3c000eb7 compiler: Debian clang version 11.0.1-2 ================================================================== BUG: KASAN: slab-out-of-bounds in fib6_nh_get_excptn_bucket net/ipv6/route.c:1604 [inline] BUG: KASAN: slab-out-of-bounds in fib6_nh_flush_exceptions+0xbd/0x360 net/ipv6/route.c:1732 Read of size 8 at addr ffff8880145c78f8 by task syz-executor.4/17760 CPU: 0 PID: 17760 Comm: syz-executor.4 Not tainted 5.12.0-rc8-syzkaller #0 Call Trace: <IRQ> __dump_stack lib/dump_stack.c:79 [inline] dump_stack+0x202/0x31e lib/dump_stack.c:120 print_address_description+0x5f/0x3b0 mm/kasan/report.c:232 __kasan_report mm/kasan/report.c:399 [inline] kasan_report+0x15c/0x200 mm/kasan/report.c:416 fib6_nh_get_excptn_bucket net/ipv6/route.c:1604 [inline] fib6_nh_flush_exceptions+0xbd/0x360 net/ipv6/route.c:1732 fib6_nh_release+0x9a/0x430 net/ipv6/route.c:3536 fib6_info_destroy_rcu+0xcb/0x1c0 net/ipv6/ip6_fib.c:174 rcu_do_batch kernel/rcu/tree.c:2559 [inline] rcu_core+0x8f6/0x1450 kernel/rcu/tree.c:2794 __do_softirq+0x372/0x7a6 kernel/softirq.c:345 invoke_softirq kernel/softirq.c:221 [inline] __irq_exit_rcu+0x22c/0x260 kernel/softirq.c:422 irq_exit_rcu+0x5/0x20 kernel/softirq.c:434 sysvec_apic_timer_interrupt+0x91/0xb0 arch/x86/kernel/apic/apic.c:1100 </IRQ> asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:632 RIP: 0010:lock_acquire+0x1f6/0x720 kernel/locking/lockdep.c:5515 Code: f6 84 24 a1 00 00 00 02 0f 85 8d 02 00 00 f7 c3 00 02 00 00 49 bd 00 00 00 00 00 fc ff df 74 01 fb 48 c7 44 24 40 0e 36 e0 45 <4b> c7 44 3d 00 00 00 00 00 4b c7 44 3d 09 00 00 00 00 43 c7 44 3d RSP: 0018:ffffc90009e06560 EFLAGS: 00000206 RAX: 1ffff920013c0cc0 RBX: 0000000000000246 RCX: dffffc0000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc90009e066e0 R08: dffffc0000000000 R09: fffffbfff1f992b1 R10: fffffbfff1f992b1 R11: 0000000000000000 R12: 0000000000000000 R13: dffffc0000000000 R14: 0000000000000000 R15: 1ffff920013c0cb4 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:267 rcu_read_lock include/linux/rcupdate.h:656 [inline] ext4_get_group_info+0xea/0x340 fs/ext4/ext4.h:3231 ext4_mb_prefetch+0x123/0x5d0 fs/ext4/mballoc.c:2212 ext4_mb_regular_allocator+0x8a5/0x28f0 fs/ext4/mballoc.c:2379 ext4_mb_new_blocks+0xc6e/0x24f0 fs/ext4/mballoc.c:4982 ext4_ext_map_blocks+0x2be3/0x7210 fs/ext4/extents.c:4238 ext4_map_blocks+0xab3/0x1cb0 fs/ext4/inode.c:638 ext4_getblk+0x187/0x6c0 fs/ext4/inode.c:848 ext4_bread+0x2a/0x1c0 fs/ext4/inode.c:900 ext4_append+0x1a4/0x360 fs/ext4/namei.c:67 ext4_init_new_dir+0x337/0xa10 fs/ext4/namei.c:2768 ext4_mkdir+0x4b8/0xc00 fs/ext4/namei.c:2814 vfs_mkdir+0x45b/0x640 fs/namei.c:3819 ovl_do_mkdir fs/overlayfs/overlayfs.h:161 [inline] ovl_mkdir_real+0x53/0x1a0 fs/overlayfs/dir.c:146 ovl_create_real+0x280/0x490 fs/overlayfs/dir.c:193 ovl_workdir_create+0x425/0x600 fs/overlayfs/super.c:788 ovl_make_workdir+0xed/0x1140 fs/overlayfs/super.c:1355 ovl_get_workdir fs/overlayfs/super.c:1492 [inline] ovl_fill_super+0x39ee/0x5370 fs/overlayfs/super.c:2035 mount_nodev+0x52/0xe0 fs/super.c:1413 legacy_get_tree+0xea/0x180 fs/fs_context.c:592 vfs_get_tree+0x86/0x270 fs/super.c:1497 do_new_mount fs/namespace.c:2903 [inline] path_mount+0x196f/0x2be0 fs/namespace.c:3233 do_mount fs/namespace.c:3246 [inline] __do_sys_mount fs/namespace.c:3454 [inline] __se_sys_mount+0x2f9/0x3b0 fs/namespace.c:3431 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x4665f9 Code: ff ff c3 66 2e 0f 1f 84 ---truncated---
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 ipv6 模块的 fib6_nh_flush_exceptions 方法中存在错误。
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 f88d8ea67fbdbac7a64bfa6ed9a2ba27bb822f74 ~ 7ba7fa78a92dc410b6f93ed73075ab669c3a0b59 -
Linux Linux 5.3 -

II. Public POCs for CVE-2021-47126

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III. Intelligence Information for CVE-2021-47126

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Other References for CVE-2021-47126 (4)

Same Patch Batch · Linux · 2024-03-15 · 26 CVEs total

CVE-2021-47111 8.8 HIGH xen-netback: take a reference to the RX task thread
CVE-2021-47131 8.1 HIGH net/tls: Fix use-after-free after the TLS device goes down and up
CVE-2021-47135 7.8 HIGH mt76: mt7921: fix possible AOOB issue in mt7921_mcu_tx_rate_report
CVE-2021-47112 7.8 HIGH x86/kvm: Teardown PV features on boot CPU as well
CVE-2021-47129 7.8 HIGH netfilter: nft_ct: skip expectations for confirmed conntrack
CVE-2021-47123 7.8 HIGH io_uring: fix ltout double free on completion race
CVE-2021-47124 7.8 HIGH io_uring: fix link timeout refs
CVE-2021-47132 7.5 HIGH mptcp: fix sk_forward_memory corruption on retransmission
CVE-2021-47130 7.5 HIGH nvmet: fix freeing unallocated p2pmem
CVE-2021-47109 7.5 HIGH neighbour: allow NUD_NOARP entries to be forced GCed
CVE-2021-47113 7.1 HIGH btrfs: abort in rename_exchange if we fail to insert the second ref
CVE-2021-47122 net: caif: fix memory leak in caif_device_notify
CVE-2021-47134 efi/fdt: fix panic when no valid fdt found
CVE-2021-47133 HID: amd_sfh: Fix memory leak in amd_sfh_work
CVE-2021-47128 bpf, lockdown, audit: Fix buggy SELinux lockdown permission checks
CVE-2021-47127 ice: track AF_XDP ZC enabled queues in bitmap
CVE-2021-47125 sch_htb: fix refcount leak in htb_parent_to_leaf_offload
CVE-2021-47121 net: caif: fix memory leak in cfusbl_device_notify
CVE-2021-47120 HID: magicmouse: fix NULL-deref on disconnect
CVE-2021-47119 ext4: fix memory leak in ext4_fill_super

Showing top 20 of 26 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2021-47126

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