Linux Kernel
CVE-2024-35976
HIGH
Severity by source
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
Local exploitation via setsockopt requires CAP_NET_ADMIN (PR:L); OOB read yields kernel memory disclosure (C:H) and crash potential (A:H) but no write primitive (I:N).
Primary rating from Vendor (416baaa9-dc9f-4396-8d5f-8c081fb06d67).
CVSS VectorVendor: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Lifecycle Timeline
6DescriptionCVE.org
In the Linux kernel, the following vulnerability has been resolved:
xsk: validate user input for XDP_{UMEM|COMPLETION}_FILL_RING
syzbot reported an illegal copy in xsk_setsockopt() [1]
Make sure to validate setsockopt() @optlen parameter.
[1]
BUG: KASAN: slab-out-of-bounds in copy_from_sockptr_offset include/linux/sockptr.h:49 [inline] BUG: KASAN: slab-out-of-bounds in copy_from_sockptr include/linux/sockptr.h:55 [inline] BUG: KASAN: slab-out-of-bounds in xsk_setsockopt+0x909/0xa40 net/xdp/xsk.c:1420 Read of size 4 at addr ffff888028c6cde3 by task syz-executor.0/7549
CPU: 0 PID: 7549 Comm: syz-executor.0 Not tainted 6.8.0-syzkaller-08951-gfe46a7dd189e #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024 Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114 print_address_description mm/kasan/report.c:377 [inline] print_report+0x169/0x550 mm/kasan/report.c:488 kasan_report+0x143/0x180 mm/kasan/report.c:601 copy_from_sockptr_offset include/linux/sockptr.h:49 [inline] copy_from_sockptr include/linux/sockptr.h:55 [inline] xsk_setsockopt+0x909/0xa40 net/xdp/xsk.c:1420 do_sock_setsockopt+0x3af/0x720 net/socket.c:2311 __sys_setsockopt+0x1ae/0x250 net/socket.c:2334 __do_sys_setsockopt net/socket.c:2343 [inline] __se_sys_setsockopt net/socket.c:2340 [inline] __x64_sys_setsockopt+0xb5/0xd0 net/socket.c:2340 do_syscall_64+0xfb/0x240 entry_SYSCALL_64_after_hwframe+0x6d/0x75 RIP: 0033:0x7fb40587de69 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fb40665a0c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 00007fb4059abf80 RCX: 00007fb40587de69 RDX: 0000000000000005 RSI: 000000000000011b RDI: 0000000000000006 RBP: 00007fb4058ca47a R08: 0000000000000002 R09: 0000000000000000 R10: 0000000020001980 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000000b R14: 00007fb4059abf80 R15: 00007fff57ee4d08 </TASK>
Allocated by task 7549: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3f/0x80 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:370 [inline] __kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:387 kasan_kmalloc include/linux/kasan.h:211 [inline] __do_kmalloc_node mm/slub.c:3966 [inline] __kmalloc+0x233/0x4a0 mm/slub.c:3979 kmalloc include/linux/slab.h:632 [inline] __cgroup_bpf_run_filter_setsockopt+0xd2f/0x1040 kernel/bpf/cgroup.c:1869 do_sock_setsockopt+0x6b4/0x720 net/socket.c:2293 __sys_setsockopt+0x1ae/0x250 net/socket.c:2334 __do_sys_setsockopt net/socket.c:2343 [inline] __se_sys_setsockopt net/socket.c:2340 [inline] __x64_sys_setsockopt+0xb5/0xd0 net/socket.c:2340 do_syscall_64+0xfb/0x240 entry_SYSCALL_64_after_hwframe+0x6d/0x75
The buggy address belongs to the object at ffff888028c6cde0 which belongs to the cache kmalloc-8 of size 8 The buggy address is located 1 bytes to the right of allocated 2-byte region [ffff888028c6cde0, ffff888028c6cde2)
The buggy address belongs to the physical page: page:ffffea0000a31b00 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888028c6c9c0 pfn:0x28c6c anon flags: 0xfff00000000800(slab|node=0|zone=1|lastcpupid=0x7ff) page_type: 0xffffffff() raw: 00fff00000000800 ffff888014c41280 0000000000000000 dead000000000001 raw: ffff888028c6c9c0 0000000080800057 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 0, migratetype Unmovable, gfp_mask 0x112cc0(GFP_USER|__GFP_NOWARN|__GFP_NORETRY), pid 6648, tgid 6644 (syz-executor.0), ts 133906047828, free_ts 133859922223 set_page_owner include/linux/page_owner.h:31 [inline] post_alloc_hook+0x1ea/0x210 mm/page_alloc.c:1533 prep_new_page mm/page_alloc.c: ---truncated---
AnalysisAI
Out-of-bounds slab read in the Linux kernel's AF_XDP socket subsystem enables a local low-privileged attacker to leak kernel heap memory contents or crash the host. The flaw in xsk_setsockopt() (net/xdp/xsk.c:1420) stems from missing validation of the caller-supplied optlen parameter for XDP_UMEM_FILL_RING and XDP_COMPLETION_FILL_RING socket options, allowing copy_from_sockptr to read 4 bytes from an undersized user-controlled buffer into adjacent slab memory. No public exploit is identified at time of analysis, and EPSS at 0.01% (2nd percentile) signals negligible observed exploitation activity; a syzbot fuzzer reproducer does exist, confirming the code path is reachable with crafted syscall sequences.
Technical ContextAI
The vulnerability resides in the XDP (eXpress Data Path) subsystem, which provides a high-performance kernel bypass mechanism allowing user-space programs to process packets before they traverse the full network stack using AF_XDP sockets. In xsk_setsockopt() at net/xdp/xsk.c:1420, when handling the XDP_UMEM_FILL_RING or XDP_COMPLETION_FILL_RING options, the kernel invokes copy_from_sockptr() to read a 4-byte ring size (u32) from user space without first asserting that optlen >= sizeof(u32). If a caller supplies an optlen smaller than 4, the copy function reads beyond the end of the allocated sockptr buffer into adjacent slab allocations. KASAN confirmed: a 4-byte read occurred 1 byte past a 2-byte allocation in the kmalloc-8 cache. CPE data (cpe:2.3:o:linux:linux_kernel) confirms Linux kernel is the sole affected product, with affected releases spanning multiple stable series up to 6.9-rc3. The assigned CWE-787 (Out-of-bounds Write) appears to be a misclassification by NVD - the KASAN trace unambiguously shows a slab read operation, which maps to CWE-125 (Out-of-bounds Read).
RemediationAI
Apply the upstream kernel patches backported across stable branches. Eight patch commits are referenced in the NVD advisory: git.kernel.org/stable/c/0b45c25d60e38f5c2cb6823f886773a34323306d, /237f3cf13b20db183d3706d997eedc3c49eacd44, /2a523f14a3f53b46ff0e1fafd215b0bc5f6783aa, /2eb979fbb2479bcd7e049f2f9978b6590dd8a0e6, /a82984b3c6a7e8c7937dba6e857ddf829d149417, /b143e19dc28c3211f050f7848d87d9b0a170e10c, /beb99266830520e15fbc6ca8cc5a5240d76851fd, and /f0a068de65d5b7358e9aff792716afa9333f3922. Upgrade to the patched kernel version provided by your Linux distribution; exact fixed versions should be confirmed from the relevant distribution security advisory. As a compensating control where immediate patching is not feasible, restrict the ability to create AF_XDP sockets by enforcing strict CAP_NET_ADMIN controls and auditing which containers or users are granted network namespace capabilities - this eliminates the attack surface with no functional impact on workloads not using XDP-based packet processing. Applying seccomp profiles that deny setsockopt calls with the AF_XDP socket level (0x11b / SOL_XDP) is an additional targeted mitigation for environments that do not use XDP.
Same weakness CWE-787 – Out-of-bounds Write
View allSame technique Buffer Overflow
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External POC / Exploit Code
Leaving vuln.today