🛡️ CVE-2023-53726 on Debian — linux

⚪ Unknown ✅ No Known Exploit OSV

N/A

CVSS Score

0 Low4 Medium7 High9 Critical10

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

Distribution advisory

This page covers CVE-2023-53726 as tracked by Debian, for the package linux. The fix is available in version 6.5.3-1; earlier versions remain affected.

How this vulnerability can be exploited

This issue can be reached with local access to the system, attack complexity is low, an attacker needs low-level privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality high, integrity none, availability high.

Affected software

DEBIAN-CVE-2023-53726 is recorded against 1 package.

linux (fixed in 6.5.3-1)

Timeline and source

Published on 22 October 2025 and last revised on 5 August 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.

References

security-tracker.debian.org (Advisory)

CVE-2023-53726 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

BellSoft Base record Ubuntu

Details

Severity Unknown

CVSS Score N/A

CVSS Vector CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

CWE N/A

Public Exploit ✅ No

Source OSV

Published 2025-10-22

Updated 2026-08-20

Modified 2026-08-05

Fix URL N/A

Affected Packages

Software	From version	Fixed in
linux	—	6.5.3-1

References

ADVISORY https://security-tracker.debian.org/tracker/CVE-2023-53726

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