CVE-2023-53726
Unknown Unknown - Not Provided
BaseFortify

Publication date: 2025-10-22

Last updated on: 2025-10-22

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: arm64: csum: Fix OoB access in IP checksum code for negative lengths Although commit c2c24edb1d9c ("arm64: csum: Fix pathological zero-length calls") added an early return for zero-length input, syzkaller has popped up with an example of a _negative_ length which causes an undefined shift and an out-of-bounds read: | BUG: KASAN: slab-out-of-bounds in do_csum+0x44/0x254 arch/arm64/lib/csum.c:39 | Read of size 4294966928 at addr ffff0000d7ac0170 by task syz-executor412/5975 | | CPU: 0 PID: 5975 Comm: syz-executor412 Not tainted 6.4.0-rc4-syzkaller-g908f31f2a05b #0 | Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/25/2023 | Call trace: | dump_backtrace+0x1b8/0x1e4 arch/arm64/kernel/stacktrace.c:233 | show_stack+0x2c/0x44 arch/arm64/kernel/stacktrace.c:240 | __dump_stack lib/dump_stack.c:88 [inline] | dump_stack_lvl+0xd0/0x124 lib/dump_stack.c:106 | print_address_description mm/kasan/report.c:351 [inline] | print_report+0x174/0x514 mm/kasan/report.c:462 | kasan_report+0xd4/0x130 mm/kasan/report.c:572 | kasan_check_range+0x264/0x2a4 mm/kasan/generic.c:187 | __kasan_check_read+0x20/0x30 mm/kasan/shadow.c:31 | do_csum+0x44/0x254 arch/arm64/lib/csum.c:39 | csum_partial+0x30/0x58 lib/checksum.c:128 | gso_make_checksum include/linux/skbuff.h:4928 [inline] | __udp_gso_segment+0xaf4/0x1bc4 net/ipv4/udp_offload.c:332 | udp6_ufo_fragment+0x540/0xca0 net/ipv6/udp_offload.c:47 | ipv6_gso_segment+0x5cc/0x1760 net/ipv6/ip6_offload.c:119 | skb_mac_gso_segment+0x2b4/0x5b0 net/core/gro.c:141 | __skb_gso_segment+0x250/0x3d0 net/core/dev.c:3401 | skb_gso_segment include/linux/netdevice.h:4859 [inline] | validate_xmit_skb+0x364/0xdbc net/core/dev.c:3659 | validate_xmit_skb_list+0x94/0x130 net/core/dev.c:3709 | sch_direct_xmit+0xe8/0x548 net/sched/sch_generic.c:327 | __dev_xmit_skb net/core/dev.c:3805 [inline] | __dev_queue_xmit+0x147c/0x3318 net/core/dev.c:4210 | dev_queue_xmit include/linux/netdevice.h:3085 [inline] | packet_xmit+0x6c/0x318 net/packet/af_packet.c:276 | packet_snd net/packet/af_packet.c:3081 [inline] | packet_sendmsg+0x376c/0x4c98 net/packet/af_packet.c:3113 | sock_sendmsg_nosec net/socket.c:724 [inline] | sock_sendmsg net/socket.c:747 [inline] | __sys_sendto+0x3b4/0x538 net/socket.c:2144 Extend the early return to reject negative lengths as well, aligning our implementation with the generic code in lib/checksum.c
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Meta Information
Published
2025-10-22
Last Modified
2025-10-22
Generated
2026-05-07
AI Q&A
2025-10-22
EPSS Evaluated
2026-05-05
NVD
EUVD
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel 6.4.0-rc4
Helpful Resources
Exploitability
CWE
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CWE ID Description
CWE-UNKNOWN
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?

This vulnerability is an out-of-bounds (OoB) access issue in the Linux kernel's arm64 checksum code. Specifically, the IP checksum function did not properly handle negative length values, which caused undefined behavior such as an out-of-bounds read. Although zero-length inputs were previously handled, negative lengths were not rejected, leading to potential memory safety issues. The fix extends the early return to also reject negative lengths, preventing this out-of-bounds access.


How can this vulnerability impact me? :

This vulnerability can lead to undefined behavior in the Linux kernel, including out-of-bounds memory reads. Such behavior can cause system instability, crashes, or potentially be exploited to leak sensitive information or escalate privileges, depending on the context in which the kernel is used.


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