{"id":"CVE-2023-53726","state":"PUBLISHED","title":"arm64: csum: Fix OoB access in IP checksum code for negative lengths","description":"In the Linux kernel, the following vulnerability has been resolved:\n\narm64: csum: Fix OoB access in IP checksum code for negative lengths\n\nAlthough commit c2c24edb1d9c (\"arm64: csum: Fix pathological zero-length\ncalls\") added an early return for zero-length input, syzkaller has\npopped up with an example of a _negative_ length which causes an\nundefined shift and an out-of-bounds read:\n\n | BUG: KASAN: slab-out-of-bounds in do_csum+0x44/0x254 arch/arm64/lib/csum.c:39\n | Read of size 4294966928 at addr ffff0000d7ac0170 by task syz-executor412/5975\n |\n | CPU: 0 PID: 5975 Comm: syz-executor412 Not tainted 6.4.0-rc4-syzkaller-g908f31f2a05b #0\n | Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/25/2023\n | Call trace:\n |  dump_backtrace+0x1b8/0x1e4 arch/arm64/kernel/stacktrace.c:233\n |  show_stack+0x2c/0x44 arch/arm64/kernel/stacktrace.c:240\n |  __dump_stack lib/dump_stack.c:88 [inline]\n |  dump_stack_lvl+0xd0/0x124 lib/dump_stack.c:106\n |  print_address_description mm/kasan/report.c:351 [inline]\n |  print_report+0x174/0x514 mm/kasan/report.c:462\n |  kasan_report+0xd4/0x130 mm/kasan/report.c:572\n |  kasan_check_range+0x264/0x2a4 mm/kasan/generic.c:187\n |  __kasan_check_read+0x20/0x30 mm/kasan/shadow.c:31\n |  do_csum+0x44/0x254 arch/arm64/lib/csum.c:39\n |  csum_partial+0x30/0x58 lib/checksum.c:128\n |  gso_make_checksum include/linux/skbuff.h:4928 [inline]\n |  __udp_gso_segment+0xaf4/0x1bc4 net/ipv4/udp_offload.c:332\n |  udp6_ufo_fragment+0x540/0xca0 net/ipv6/udp_offload.c:47\n |  ipv6_gso_segment+0x5cc/0x1760 net/ipv6/ip6_offload.c:119\n |  skb_mac_gso_segment+0x2b4/0x5b0 net/core/gro.c:141\n |  __skb_gso_segment+0x250/0x3d0 net/core/dev.c:3401\n |  skb_gso_segment include/linux/netdevice.h:4859 [inline]\n |  validate_xmit_skb+0x364/0xdbc net/core/dev.c:3659\n |  validate_xmit_skb_list+0x94/0x130 net/core/dev.c:3709\n |  sch_direct_xmit+0xe8/0x548 net/sched/sch_generic.c:327\n |  __dev_xmit_skb net/core/dev.c:3805 [inline]\n |  __dev_queue_xmit+0x147c/0x3318 net/core/dev.c:4210\n |  dev_queue_xmit include/linux/netdevice.h:3085 [inline]\n |  packet_xmit+0x6c/0x318 net/packet/af_packet.c:276\n |  packet_snd net/packet/af_packet.c:3081 [inline]\n |  packet_sendmsg+0x376c/0x4c98 net/packet/af_packet.c:3113\n |  sock_sendmsg_nosec net/socket.c:724 [inline]\n |  sock_sendmsg net/socket.c:747 [inline]\n |  __sys_sendto+0x3b4/0x538 net/socket.c:2144\n\nExtend the early return to reject negative lengths as well, aligning our\nimplementation with the generic code in lib/checksum.c","publishedAt":"2025-10-22T13:23:55.896Z","updatedAt":"2026-10-15T21:41:34.644Z","severity":{"score":7.1,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"5777eaed566a1d63e344d3dd8f2b5e33be20643e","status":"affected","lessThan":"5a85727239a23de1cc8d93985f1056308128f3e2","versionType":"git"},{"version":"5777eaed566a1d63e344d3dd8f2b5e33be20643e","status":"affected","lessThan":"9a43563cfd6b9200ff2f76b3f9fcdcb217ceb523","versionType":"git"},{"version":"5777eaed566a1d63e344d3dd8f2b5e33be20643e","status":"affected","lessThan":"ba0b46166b8e547024d02345a68b747841931ad2","versionType":"git"},{"version":"5777eaed566a1d63e344d3dd8f2b5e33be20643e","status":"affected","lessThan":"a5ad2f87d8e74e351d3f500ad9d5b3a5653e1c6f","versionType":"git"},{"version":"5777eaed566a1d63e344d3dd8f2b5e33be20643e","status":"affected","lessThan":"fcdf904e866de0e3715835e50409fda3b2590527","versionType":"git"},{"version":"5777eaed566a1d63e344d3dd8f2b5e33be20643e","status":"affected","lessThan":"8bd795fedb8450ecbef18eeadbd23ed8fc7630f5","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["arch/arm64/lib/csum.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.6","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.6","versionType":"semver"},{"version":"5.10.195","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.132","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.53","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.4.16","status":"unaffected","lessThanOrEqual":"6.4.*","versionType":"semver"},{"version":"6.5.3","status":"unaffected","lessThanOrEqual":"6.5.*","versionType":"semver"},{"version":"6.6","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["arch/arm64/lib/csum.c"]}],"references":["https://git.kernel.org/stable/c/5a85727239a23de1cc8d93985f1056308128f3e2","https://git.kernel.org/stable/c/9a43563cfd6b9200ff2f76b3f9fcdcb217ceb523","https://git.kernel.org/stable/c/ba0b46166b8e547024d02345a68b747841931ad2","https://git.kernel.org/stable/c/a5ad2f87d8e74e351d3f500ad9d5b3a5653e1c6f","https://git.kernel.org/stable/c/fcdf904e866de0e3715835e50409fda3b2590527","https://git.kernel.org/stable/c/8bd795fedb8450ecbef18eeadbd23ed8fc7630f5"],"weaknesses":[],"ingestedAt":"2026-10-29T20:06:33.064Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2023/53xxx/CVE-2023-53726.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2023-53726","state":"PUBLISHED","datePublished":"2025-10-22T13:23:55.896Z","dateUpdated":"2026-10-15T21:41:34.644Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2025-10-22T13:21:37.348Z"},"containers":{"cna":{"title":"arm64: csum: Fix OoB access in IP checksum code for negative lengths","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\narm64: csum: Fix OoB access in IP checksum code for negative lengths\n\nAlthough commit c2c24edb1d9c (\"arm64: csum: Fix pathological zero-length\ncalls\") added an early return for zero-length input, syzkaller has\npopped up with an example of a _negative_ length which causes an\nundefined shift and an out-of-bounds read:\n\n | BUG: KASAN: slab-out-of-bounds in do_csum+0x44/0x254 arch/arm64/lib/csum.c:39\n | Read of size 4294966928 at addr ffff0000d7ac0170 by task syz-executor412/5975\n |\n | CPU: 0 PID: 5975 Comm: syz-executor412 Not tainted 6.4.0-rc4-syzkaller-g908f31f2a05b #0\n | Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/25/2023\n | Call trace:\n |  dump_backtrace+0x1b8/0x1e4 arch/arm64/kernel/stacktrace.c:233\n |  show_stack+0x2c/0x44 arch/arm64/kernel/stacktrace.c:240\n |  __dump_stack lib/dump_stack.c:88 [inline]\n |  dump_stack_lvl+0xd0/0x124 lib/dump_stack.c:106\n |  print_address_description mm/kasan/report.c:351 [inline]\n |  print_report+0x174/0x514 mm/kasan/report.c:462\n |  kasan_report+0xd4/0x130 mm/kasan/report.c:572\n |  kasan_check_range+0x264/0x2a4 mm/kasan/generic.c:187\n |  __kasan_check_read+0x20/0x30 mm/kasan/shadow.c:31\n |  do_csum+0x44/0x254 arch/arm64/lib/csum.c:39\n |  csum_partial+0x30/0x58 lib/checksum.c:128\n |  gso_make_checksum include/linux/skbuff.h:4928 [inline]\n |  __udp_gso_segment+0xaf4/0x1bc4 net/ipv4/udp_offload.c:332\n |  udp6_ufo_fragment+0x540/0xca0 net/ipv6/udp_offload.c:47\n |  ipv6_gso_segment+0x5cc/0x1760 net/ipv6/ip6_offload.c:119\n |  skb_mac_gso_segment+0x2b4/0x5b0 net/core/gro.c:141\n |  __skb_gso_segment+0x250/0x3d0 net/core/dev.c:3401\n |  skb_gso_segment include/linux/netdevice.h:4859 [inline]\n |  validate_xmit_skb+0x364/0xdbc net/core/dev.c:3659\n |  validate_xmit_skb_list+0x94/0x130 net/core/dev.c:3709\n |  sch_direct_xmit+0xe8/0x548 net/sched/sch_generic.c:327\n |  __dev_xmit_skb net/core/dev.c:3805 [inline]\n |  __dev_queue_xmit+0x147c/0x3318 net/core/dev.c:4210\n |  dev_queue_xmit include/linux/netdevice.h:3085 [inline]\n |  packet_xmit+0x6c/0x318 net/packet/af_packet.c:276\n |  packet_snd net/packet/af_packet.c:3081 [inline]\n |  packet_sendmsg+0x376c/0x4c98 net/packet/af_packet.c:3113\n |  sock_sendmsg_nosec net/socket.c:724 [inline]\n |  sock_sendmsg net/socket.c:747 [inline]\n |  __sys_sendto+0x3b4/0x538 net/socket.c:2144\n\nExtend the early return to reject negative lengths as well, aligning our\nimplementation with the generic code in lib/checksum.c"}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"5777eaed566a1d63e344d3dd8f2b5e33be20643e","status":"affected","lessThan":"5a85727239a23de1cc8d93985f1056308128f3e2","versionType":"git"},{"version":"5777eaed566a1d63e344d3dd8f2b5e33be20643e","status":"affected","lessThan":"9a43563cfd6b9200ff2f76b3f9fcdcb217ceb523","versionType":"git"},{"version":"5777eaed566a1d63e344d3dd8f2b5e33be20643e","status":"affected","lessThan":"ba0b46166b8e547024d02345a68b747841931ad2","versionType":"git"},{"version":"5777eaed566a1d63e344d3dd8f2b5e33be20643e","status":"affected","lessThan":"a5ad2f87d8e74e351d3f500ad9d5b3a5653e1c6f","versionType":"git"},{"version":"5777eaed566a1d63e344d3dd8f2b5e33be20643e","status":"affected","lessThan":"fcdf904e866de0e3715835e50409fda3b2590527","versionType":"git"},{"version":"5777eaed566a1d63e344d3dd8f2b5e33be20643e","status":"affected","lessThan":"8bd795fedb8450ecbef18eeadbd23ed8fc7630f5","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["arch/arm64/lib/csum.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.6","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.6","versionType":"semver"},{"version":"5.10.195","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.132","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.53","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.4.16","status":"unaffected","lessThanOrEqual":"6.4.*","versionType":"semver"},{"version":"6.5.3","status":"unaffected","lessThanOrEqual":"6.5.*","versionType":"semver"},{"version":"6.6","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["arch/arm64/lib/csum.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/5a85727239a23de1cc8d93985f1056308128f3e2"},{"url":"https://git.kernel.org/stable/c/9a43563cfd6b9200ff2f76b3f9fcdcb217ceb523"},{"url":"https://git.kernel.org/stable/c/ba0b46166b8e547024d02345a68b747841931ad2"},{"url":"https://git.kernel.org/stable/c/a5ad2f87d8e74e351d3f500ad9d5b3a5653e1c6f"},{"url":"https://git.kernel.org/stable/c/fcdf904e866de0e3715835e50409fda3b2590527"},{"url":"https://git.kernel.org/stable/c/8bd795fedb8450ecbef18eeadbd23ed8fc7630f5"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H","baseScore":7.1,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - The trigger is a local `sendmsg()`/`sendto()` on an AF_PACKET socket with a crafted virtio_net_hdr, driving the local TX GSO segmentation path into `gso_make_checksum()` with a negative length. No remote peer input reaches `do_csum()` with a negative length.\nAC:L - The attacker fully controls `csum_start`, `csum_offset` and `gso_size` in the virtio_net_hdr and thus deterministically produces the negative `plen`; there is no race, no memory-layout dependency, and no reliance on unusual configuration for the underlying arm64 kernel to hit the bad path.\nPR:L - AF_PACKET socket creation checks `ns_capable(net->user_ns, CAP_NET_RAW)`, so an unprivileged user obtains it with `unshare -Urn`, which also confers CAP_NET_ADMIN in that netns to disable offloads and force software GSO segmentation.\nUI:N - The attacker triggers the whole sequence from its own process with a socket and a single send; no victim action or cooperation is involved.\nS:U - The faulty read and the undefined shift both occur within kernel context on behalf of the calling task, with no crossing of a VM, IOMMU, or other security-authority boundary.\nC:H - The fix addresses an out-of-bounds read in the checksum primitive with an attacker-influenced negative length, and the resulting checksum is emitted in the outgoing packet, exposing a function of memory outside the intended range; sufficiently negative lengths wrap `len + offset - 8` positive and let the main loop walk arbitrary kernel memory.\nI:N - `do_csum()` performs only loads; the sole downstream effect is a bogus checksum value written into the attacker's own outgoing packet, with no modification of kernel memory or other principals' data.\nA:H - The condition is reported as a KASAN slab-out-of-bounds BUG, which panics kernels built with KASAN or running `panic_on_warn`/`kasan.fault=panic`, and an unbounded negative length drives the 64-byte-stride loop off the end of the object into unmapped memory, oopsing the kernel."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-05T09:15:42.563Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.6","versionEndExcluding":"5.10.195"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.6","versionEndExcluding":"5.15.132"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.6","versionEndExcluding":"6.1.53"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.6","versionEndExcluding":"6.4.16"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.6","versionEndExcluding":"6.5.3"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.6","versionEndExcluding":"6.6"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2023-53726","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"version":"2.0.3","timestamp":"2026-10-15T21:36:49.302091Z"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-15T21:41:34.644Z"}}]}}}